obesity
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Obesity

Obesity

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Although obesity, which indicates excessive accumulation of fat tissue with a corresponding increase in size, has been the focus of medical interest since antiquity, it has not been well defined. Moderate stores of fat are desirable and indicate normal nutrition. Since only an excess of the physiologically desirable is regarded as abnormal, a quantitative, even arbitrary, element enters into the definition. A clinician of the last century (Ebstein 1882) divided obesity into three stages: the enviable, the comical, and the pitiable. In contemporary American society no stage would be considered “enviable.” Even mild degrees of excess weight, or those that indicate abundant normal growth, are condemned.

During the past half century, obesity has customarily been equated with overweight in relation to an “average” figure for height, age, and sex. Since in Western society weight commonly increases with age, it was considered a further refinement to refer to the weight of the young adult person as the “ideal.” Life insurance companies, which need a statistical approach for quick evaluation of a large number of people, have branded any excess weight as undesirable. Clinically, it is doubtful whether such a statistical concept of “normal” or “ideal” weight is valid. A recent examination of the total population of a certain area in the south of Sweden, for example, revealed that as much as 70 per cent of the female population over 40 years of age were 10 kilograms “overweight” and 10 per cent were overweight by 30 kilograms or more (Bjurulf & Lindgren 1964).

Many other objections have been raised against a rigid statistical approach. It has been criticized as being based on the implicit assumption that all body weight is equivalent and that overweight is a measure of relative fatness. Keys and Brozek (1953), who first gathered extensive evidence against the blind use of statistics, particularly in regard to moderately overweight persons, considered some judicious pinches of various skin folds a more scientific way of estimating fatness. Refinements of this biological approach include the use of skin-fold calipers, soft-tissue roentgenograms, and estimates of the total body water through densitometry. These newer methods aid in obtaining more accurate measurements of the body fat in relation to the lean tissue (von Dobeln 1964).

There is increasing awareness that clinical obesity does not represent just an extreme on the normal distribution curve for weight, but that it is a symptom of true abnormalities, an expression of a variety of underlying clinical disturbances (MacBryde 1964). There is increasing recognition that the term refers to a variety of decidedly different clinical pictures. Obesity that develops early in life, in infancy or before puberty, has an entirely different course and significance from the gradual increase in weight in middle life (Bruch 1955).

Entirely different problems are encountered in (1) those whose weight is stable or who have arrived at the stationary stage of obesity and (2) those who are in the active phase of progressively increasing weight or who, with constant fluctuation, show dramatic weight losses during which the fat seems to melt away, only to be regained even more rapidly. The clinical picture and the pathological processes are different again in superobese people who achieve a tremendous size, with weight in excess of 300 pounds—reaching up to 700 or 800. At the present stage of our knowledge, or rather ignorance, it is not possible to differentiate between these different forms of obesity on the basis of any laboratory test; thus far it can be done only through evaluation of the whole development and reaction pattern (Bruch 1957a).

Economic and sociological factors . Regardless of the physiological and psychological aspects to be discussed later, external factors influence the occurrence of obesity to a conspicuous degree. In the United States, obesity has been called the number one health problem. Other affluent countries, too, express concern with overnutrition as a not altogether desirable by-product of increased and improved food consumption and labor-saving devices.

Human history has been determined to a large extent by the search for sufficient food. Malnutrition is still prevalent in underdeveloped countries with inadequate nutritional resources, and starvation is a specter that even today threatens large sections of mankind. Such abundance of food for large population groups is historically very recent, and geographically it is limited to a few overprivileged countries.

Yet the condition of obesity has been familiar to man since the dawn of history. The oldest representation of the human form, the “Venus of Wilendorf,” shows marked obesity, and so do other paleontological figurines. The taste for fat women persisted into the Neolithic period. It is not known whether these “Venuses” are realistic representations or whether they represent an artistic ideal, a dream of abundance and fertility.

In primitive society, a yearning for fatness persists. Cloete (1953, p. 119) describes the attitude of the typical South African who works for the white man: “. . . and what is his heart’s desire? Fat above all things. To be fat himself, to have a fat wife and children and fat cattle. This is the native’s dream, the Biblical dream of plenty in a starving land.”

A similar primitive desire for fatness was conspicuous during the 1930s among the mothers of a large group of obese children who were studied in New York City (Bruch 1940). Many of the women had been poor immigrants who had suffered hunger during their early lives. They did not understand why anyone should object to a child’s being big and fat, which to them indicated success and freedom from want.

Even in the United States, traditionally the country of abundance, nutritional deficiency diseases were the object of concern fifty years ago; today they have become quite rare. In the last fifty years, American children, both of native and foreign-born parents, have become 6-8 per cent taller and 1215 per cent heavier than their parents, and maturation and puberty occur at an earlier age. The same observation is being made in Japan, where the new generation, under the influence of improved nutrition, is outgrowing the short stature of the parents.

Adequate food supply is thus a prerequisite for optimum weight and physical development. Yet under the conditions of abundance, only a certain number of people become obese. A rich literature exists on the occurrence of obesity in different societies and eras, and on outstanding individuals who have been fat. Fascinating as these reports are, they have the value only of anecdotal contributions and are based on hearsay tales, old chronicles, and speculation (Bruch 1957a; Clauser & Spranger 1957).

In spite of the great public interest in obesity, systematic inquiries into its sociological aspects are conspicuously rare. Public health figures indicate a change in the weight of adult Americans: since 1912 the average weight of women has decreased by 5 pounds, whereas the average man is 5 pounds heavier. A detailed evaluation of a large unselected population sample—1,600 adults living in a central residential area of New York City—led to the discovery of a striking relationship between obesity and social class (Moore et al. 1962). Obesity occurred seven times more frequently among women of the lowest socioeconomic level than among those of the highest level; among men the same relationship existed, although to a lesser degree. As other studies also noted, obesity was found to increase with age.

Similar observations are reported in the south of Sweden, where the weight of women in the upper classes is lower and shows less variability than that of women of poorer economic background. However, men in the lower sociological group in Sweden do not tend to be overweight (Andersen & Esmann 1957).

A recent German study gives a different picture (Pflanz 1963). Information on social factors was obtained for 10,000 patients who were seen during one year at the medical clinic of the University of Giessen. A weight excess of 15 kilograms, indicating undisputed obesity, was observed in a sample of about 1,000 patients. This study revealed that the sociological factors associated with obesity were quite different in men and women. Conspicuously often, obesity occurred in men who had been only children. No such difference between the sexes was observed in those who came from a large sibling group. Single and divorced women and those living in cities were less obese than married and widowed women and those living in rural surroundings. Analysis according to social class revealed the greatest differences. In the group of independent farmers and small-business people, obesity was observed at approximately the same frequency in men and women. In the highest and lowest social class, the sex distributions went in opposite directions. Obesity was more frequent in women of the lowest class and in men of the highest class. It seems that under the special conditions of German culture, obesity in men has an entirely different sociological significance from that in women; in men it seems to add to their sense of power and prestige.

Physiological factors . The question of what causes obesity has challenged physicians since antiquity. Two lines of reasoning can be recognized throughout the medical literature: one suggests that obesity is due to some innate inherited factors and is therefore an unalterable fate; the other suggests that it is the result of deplorable personal habits—overeating and inactivity—that are morally condemned as greed and laziness. Scientific understanding has been delayed by the tendency to consider heredity and environmental factors as mutually exclusive. They are not only not opposed but interact and influence each other in many ways (Stern 1949). This clinical deduction now finds support from genetics, namely, from recent evidence that in the cells of higher organisms a large part of the genetic material remains inactive and that the level of activity of a gene depends on environmental factors. Changes in diet and hormonal secretion may serve to activate certain genes. They in turn are influenced by living conditions, climate, and the emotional state of the organism.

The case for heredity is easily made in regard to obesity. A high family incidence is reported by many different investigators (Bruch 1957a; Davenport 1923). Of course, it is just as easy to demonstrate that these families indulge in rich meals and tend to avoid physical activities.

Other evidence of inherent factors is the prevalence of certain constitutional types. In a group of 180 obese adolescent girls, there was an expected high proportion of endomorphic types, but also a high incidence of mesomorphic types (Seltzer & Mayer 1964). A group of 250 obese boys and girls tended to be taller and to mature earlier than their age peers of normal weight (Bruch 1939a). An anthropological study of adult obese women showed the prevalence of a certain body type, namely, juvenile proportions that are associated with early maturity [Ange] 1949; see also Psychology, article on Constitutional Psychology].

Micromorphologic study shows that fat tissue varies greatly in size and number of cells (Hirsch & Goldrick 1964). It appears that the size of the cell varies with nutritional factors, whereas the number of cells is determined by endogenous, probably genetic, factors. Individuals with the same thickness of subcutaneous fat may have different morphologic tissue structure. Coronary sclerosis appears to be associated with large fat cells but not with a high cell count (Bjurulf 1964).

Powerful support for the genetic view came from the discovery of certain strains of mice that grew fat under ordinary laboratory conditions. As many as 15 types of obesity, with different hereditary, metabolic, regulatory, eating, and activity disturbances, have been recognized in the mouse (Mayer 1963). It is questionable whether any of them has an equivalent in human obesity. The great merit of these extensive studies is the clarity with which they demonstrate the way multiple factors interact and how etiological and pathogenetic factors can and need to be separated.

Clinical investigations reflect this stimulus in the greater diversification of problems that are being studied. “Metabolism,” a generation ago, referred to the balance between caloric intake and output. Metabolic studies today are directed toward clarifying the transformation of various foodstuffs into the metabolites that are deposited in the tissues. There is increasing evidence that there are forms of human obesity that are characterized by the increased formation of fatty acids from glucose and other foodstuffs and their decreased release from fat deposits. Various pathways of the transfer and synthesis of fatty acids have been clarified (Elovson 1964; Gordon 1964). It has been recognized that the fat tissues themselves play a role in this process and that hormones enter into the delicate balance between lipogenesis and fat mobilization in various ways (Dole & Hirsch 1960). Once lipogenesis is increased, it cannot be reversed by simple dieting. The fat person’s claim, “Everything I eat turns into fat,” and his sad experience that the painfully lost weight is readily regained, now has some scientific support. Other metabolic work deals with disturbances in the carbohydrate metabolisms, with differences in the glucostatic regulations (Mayer 1953).

Another factor leading to disordered weight is found in disturbances in the regulatory mechanisms. Since the beginning of the century, it has been recognized that obesity may develop after midbrain lesions, in the presence of tumors, or following encephalitis (Bruch 1939b). Extensive animal studies with experimentally produced microscopic lesions in the hypothalamus and other midbrain regions have elucidated the importance of different cell groups in influencing appetite and the experience of satiation, and thus weight regulation. Here again, newer studies emphasize the complexity of the problem, namely, that not only the eating function is affected by these operations but also spontaneous activity and motivation (Kennedy 1964). Proven anatomical lesions are rare in humans, and there has been speculation about possible functional weakness of the regulatory “centers,” some aspects of which will be discussed in the section on psychological factors.

Furthermore, animal experimentation has also demonstrated that environmental factors alone can result in severe obesity. If young rats are allowed food only two hours per day, they become markedly obese, with increased lipid synthesis in the adipose tissue, in contrast to litter mates who have free access to food and grow into normal rats (Hollifield & Parson 1962). The gain in weight continues, with voracious eating, when the restricted rats are restored to normal feeding. However, the cycle is interrupted, with corresponding metabolic changes, after a period of fasting.

Psychological aspects . Throughout the ages, popular opinion has attributed definite, although contradictory, character traits to fat people that reflect changing concepts of obesity. Attention has been focused on the inherent temperament of the fat person, or on the consequences of being fat and the insults of a derogatory social climate. The contribution of psychological factors to the development of obesity has been recognized only recently.

Systematic psychological studies have led to better understanding and clinical management of obese people, and they have also revealed the complexity of the problem. Psychiatric observations first emphasized the need for differentiating among several types of human obesity and recognized overeating and inactivity as manifestations of underlying emotional and personality disturbances (Bruch 1957a).

The psychiatric problems of obesity are far from uniform (Bruch 1957b). It is not possible to speak of the psychodynamics of one basic personality type or even to describe one single psychological feature as characteristic of all obese people. Obesity may be associated with every conceivable psychiatric disorder, with neurosis as well as psychosis. Psychological problems can be recognized under two different conditions. In some patients with many signs of disturbed behavior and adaption, obesity is intrinsically interwoven with their whole development; others become obese as a reaction to some traumatic event. It is in the latter form that the significance of psychological factors was first recognized. Obesity seems to serve as an equivalent for a depressive reaction in people who in other respects have the capacity for adequate functioning.

The total picture is much more disturbed in the developmental obesity that occurs in children and adolescents who grow up in families in which they are treated as objects—precious or hated possessions that are overstuffed with food and shielded from, or not trusted with, the ordinary tasks of life. In many respects their behavior and psychological reactions resemble those of the preschizophrenic stage. Such patients may become overtly schizophrenic when the demands of life become too threatening. Enforced reducing at this time may precipitate the manifest psychosis. Overeating and inactivity appear as central symptoms in the patient’s whole development and often reflect severe intrafamilial pathology. Such patients parallel preschizophrenic development in their general immaturity, social withdrawal, and body image disturbances (Bruch 1958).

Psychological and psychiatric studies of obesity have become so numerous that it is impossible even to enumerate them in a brief review. Various investigators have focused on different traits in an effort at classification. Stunkard (1959a), for instance, differentiates various forms of obesity according to eating patterns. He has also studied the extent and psychodynamic aspects of inactivity (Dorris & Stunkard 1957).

Psychoanalytic thinking has played an important role in the psychological study of obesity and has helped to clarify the conflicts and motivations that underlie overeating. Food is symbolically equated with an insatiable desire for unattainable love, but also with inhibited destructive impulses. Food intake may reflect self-indulgence, the desire for sexual gratification, or, the wish to be pregnant; it also may represent punishment of forbidden impulses. Preoccupation with food may appear as helpless, dependent clinging to parents or as hostile rejection of them.

In recent years a skeptical note can be recognized in psychiatric writings. The question has been raised whether the observations made on selected patients undergoing extensive psychoanalysis could and should be generalized to apply to the enormous group of obese patients not so extensively studied and observed. There is also need to differentiate between the psychological forces that lead to obesity and the psychological suffering resulting from it. Monello and Mayer (1963) observed that the psychological responses of a group of obese adolescents were similar to those of a minority group. They also noted that the obese child came from a nonunified family with poor sociability and was afraid to leave home. In a sociological study in New York City, obese persons gave more pathological responses on nine measures of mental health (Moore et al. 1962). For three of these measures—immaturity, suspiciousness, and rigidity—the results were statistically significant. These observations suggest that serious emotional disturbances may be present in obese people other than those who were actually studied.

There has also been a decided change in the direction and emphasis of psychiatric inquiry. Instead of focusing exclusively on the symbolic meaning of the disturbed behavior, a more basic theoretical question has been raised: How does it happen that a body function becomes capable of being misused in the service of motivational conflicts and disturbed interpersonal relations? It has been recognized that deficits in perception and conceptualization are important factors in the psychopathology of obese patients. Inability to identify correctly hunger and satiation is conspicuous among many other indications of falsified awareness of bodily needs, emotional states, and interpersonal situations. Patients with such disturbances have difficulty in drawing correct conceptual conclusions about sensations and impulses arising from within and differentiating them from those impinging from the outside [Bruch 1961; see also Body Image].

This failure to develop an integrated and differentiated concept of a bodily self and psychological identity could be related to a deficit in earliest learning experiences, namely, the absence of confirmation of child-initiated impulses. The importance of disturbed family influences had been recognized much earlier (Bruch & Touraine 1940), but as long as the abnormal interaction was related entirely to emotional experiences, this basic disturbance in conceptual awareness remained unclear. The importance of conceptual awareness has been demonstrated experimentally. When measured amounts of food were introduced directly into the stomach, marked individual differences were observed in the accuracy of recognizing whether, and how much, food had been given. Some healthy, normal subjects were consistently accurate. Obese patients were significantly less accurate. Independently, Stunkard (1959b) observed that obese patients frequently failed to feel hungry in the presence of stomach contractions or to recognize such contractions.

A comprehensive review in a limited space of ongoing research on obesity offers severe, even unsurmountable difficulties. These very difficulties signify a desirable and much needed development. They indicate that extensive research on this topic is being performed by investigators in many different disciplines. The multitude of new findings may appear confusing and contradictory; yet there is slowly developing a convergence of opinion that, contrary to old concepts, obesity is not a uniform or simple condition but a symptom of multiple interaction of various factors, only a few of which have thus far been clearly recognized.

This whole line of work is still very much in the beginning stages, but it promises a better understanding of the problem through integrating findings in various fields of research. From the psychiatrist’s point of view, patients suffering from obesity go through life with inadequate guideposts for orienting themselves about their own functioning and their relationships with others. They develop inaccurate behavior that becomes more and more inappropriate as, with their increasing age, the demands of life become more and more complex.

Hilde Bruch

[See alsoFood, article onConsumption Patterns; Psychosomatic Illness.]

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Bjurulf, P.; and Lindgren, G. 1964 A Preliminary Study on Overweight in the South of Sweden. Pages 9-15 in Gunnar Blix (editor), Occurrences, Causes and Prevention of Overnutrition. Uppsala (Sweden): Almqvist & Wiksell.

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Bruch, Hilde 1939b The Froehlich Syndrome. American Journal of Diseases of Children 58:1282-1289. BRUCH, HILDE 1940 Obesity in Childhood. Part 3: Physiologic and Psychologic Aspects of the Food Intake of Obese Children. American Journal of Diseases of Children 59:739-781.

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Bruch, Hilde 1961 Transformation of Oral Impulses in Eating Disorders: A Conceptual Approach. Psychiatric Quarterly 35:458-481.

Bruch, Hilde; and Touraine, Grace 1940 Obesity in Childhood. Part 5: The Family Frame of Obese Children. Psychosomatic Medicine 2:141-206.

Clauser, G.; and Spranger, J. 1957 Hinweise auf die Aetiologie der Fettund Magersucht aus Volkstum, Kunst, Medizingeschichte und Wissenschaft. Münchener medizinische Wochenschrift 99:53-58.

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Obesity

Obesity

Definition

Obesity is an abnormal accumulation of body fat, usually 20% or more over an individual's ideal body weight. Obesity is associated with increased risk of illness, disability, and death.

The branch of medicine that deals with the study and treatment of obesity is known as bariatrics. As obesity has become a major health problem in the United States, bariatrics has become a separate medical and surgical specialty.

Description

Obesity traditionally has been defined as a weight at least 20% above the weight corresponding to the lowest death rate for individuals of a specific height, gender, and age (ideal weight). Twenty to forty percent over ideal weight is considered mildly obese; 40-100% over ideal weight is considered moderately obese; and 100% over ideal weight is considered severely, or morbidly, obese. More recent guidelines for obesity use a measurement called BMI (body mass index) which is the individual's weight multiplied by 703 and then divided by twice the height in inches. BMI of 25.9-29 is considered overweight; BMI over 30 is considered obese. Measurements and comparisons of waist and hip circumference can also provide some information regarding risk factors associated with weight. The higher the ratio, the greater the chance for weight-associated complications. Calipers can be used to measure skin-fold thickness to determine whether tissue is muscle (lean) or adipose tissue (fat).

Much concern has been generated about the increasing incidence of obesity among Americans. Some studies have noted an increase from 12% to 18% occurring between 1991 and 1998. Other studies have actually estimated that a full 50% of all Americans are overweight. The World Health Organization terms obesity a worldwide epidemic, and the diseases which can occur due to obesity are becoming increasingly prevalent.

Excessive weight can result in many serious, potentially life-threatening health problems, including hypertension, Type II diabetes mellitus (non-insulin dependent diabetes), increased risk for coronary disease, increased unexplained heart attack, hyperlipidemia, infertility, and a higher prevalence of colon, prostate, endometrial, and, possibly, breast cancer. Approximately 300,000 deaths a year are attributed to obesity, prompting leaders in public health, such as former Surgeon General C. Everett Koop, M.D., to label obesity "the second leading cause of preventable deaths in the United States."

Causes and symptoms

The mechanism for excessive weight gain is clearmore calories are consumed than the body burns, and the excess calories are stored as fat (adipose) tissue. However, the exact cause is not as clear and likely arises from a complex combination of factors. Genetic factors significantly influence how the body regulates the appetite and the rate at which it turns food into energy (metabolic rate). Studies of adoptees confirm this relationshipthe majority of adoptees followed a pattern of weight gain that more closely resembled that of their birth parents than their adoptive parents. A genetic predisposition to weight gain, however, does not automatically mean that a person will be obese. Eating habits and patterns of physical activity also play a significant role in the amount of weight a person gains. Recent studies have indicated that the amount of fat in a person's diet may have a greater impact on weight than the number of calories it contains. Carbohydrates like cereals, breads, fruits, and vegetables and protein (fish, lean meat, turkey breast, skim milk) are converted to fuel almost as soon as they are consumed. Most fat calories are immediately stored in fat cells, which add to the body's weight and girth as they expand and multiply. A sedentary lifestyle, particularly prevalent in affluent societies, such as in the United States, can contribute to weight gain. Psychological factors, such as depression and low self-esteem may, in some cases, also play a role in weight gain.

Height And Weight Goals
Men
Height Small Frame Medium Frame Large Frame
52 53 54 128-134 lbs. 130-136 132-138 131-141 lbs. 133-143 135-145 138-150 lbs. 140-153 142-153
55 56 57 134-140 136-142 138-145 137-148 139-151 142-154 144-160 146-164 149-168
58 59 510 140-148 142-151 144-154 145-157 148-160 151-163 152-172 155-176 158-180
511 60 61 146-157 159-160 152-164 154-166 157-170 160-174 161-184 164-188 168-192
62 63 64 155-168 158-172 162-176 164-178 167-182 171-187 172-197 176-202 181-207
Women
Height Small Frame Medium Frame Large Frame
410 411 50 102-111 lbs. 103-113 104-115 109-121 lbs. 111-123 113-126 118-131 lbs. 120-134 112-137
51 52 53 106-118 108-121 111-124 115-129 118-132 121-135 125-140 128-143 131-147
54 55 56 114-127 117-130 120-133 124-141 127-141 130-144 137-151 137-155 140-159
57 58 59 123-136 126-139 129-142 133-147 136-150 139-153 143-163 146-167 149-170
510 511 60 132-145 135-148 138-151 142-156 145-159 148-162 152-176 155-176 158-179

At what stage of life a person becomes obese can affect his or her ability to lose weight. In childhood, excess calories are converted into new fat cells (hyperplastic obesity), while excess calories consumed in adulthood only serve to expand existing fat cells (hypertrophic obesity). Since dieting and exercise can only reduce the size of fat cells, not eliminate them, persons who were obese as children can have great difficulty losing weight, since they may have up to five times as many fat cells as someone who became overweight as an adult.

Obesity can also be a side effect of certain disorders and conditions, including:

  • Cushing's syndrome, a disorder involving the excessive release of the hormone cortisol
  • hypothyroidism, a condition caused by an underactive thyroid gland
  • neurologic disturbances, such as damage to the hypothalamus, a structure located deep within the brain that helps regulate appetite
  • consumption of such drugs as steroids, antipsychotic medications, or antidepressants

The major symptoms of obesity are excessive weight gain and the presence of large amounts of fatty tissue. Obesity can also give rise to several secondary conditions, including:

  • arthritis and other orthopedic problems, such as lower back pain
  • hernias
  • heartburn
  • adult-onset asthma
  • gum disease
  • high cholesterol levels
  • gallstones
  • high blood pressure
  • menstrual irregularities or cessation of menstruation (amenorhhea)
  • decreased fertility, and pregnancy complications
  • shortness of breath that can be incapacitating
  • sleep apnea and sleeping disorders
  • skin disorders arising from the bacterial breakdown of sweat and cellular material in thick folds of skin or from increased friction between folds
  • emotional and social problems

Diagnosis

Diagnosis of obesity is made by observation and by comparing the patient's weight to ideal weight charts. Many doctors and obesity researchers refer to the body mass index (BMI), which uses a height-weight relationship to calculate an individual's ideal weight and personal risk of developing obesity-related health problems. Physicians may also obtain direct measurements of an individual's body fat content by using calipers to measure skin-fold thickness at the back of the upper arm and other sites. The most accurate means of measuring body fat content involves immersing a person in water and measuring relative displacement; however, this method is very impractical and is usually only used in scientific studies requiring very specific assessments. Women whose body fat exceeds 30% and men whose body fat exceeds 25% are generally considered obese.

Doctors may also note how a person carries excess weight on his or her body. Studies have shown that this factor may indicate whether or not an individual has a predisposition to develop certain diseases or conditions that may accompany obesity. "Apple-shaped" individuals who store most of their weight around the waist and abdomen are at greater risk for cancer, heart disease, stroke, and diabetes than "pear-shaped" people whose extra pounds settle primarily in their hips and thighs.

Treatment

Treatment of obesity depends primarily on how overweight a person is and his or her overall health. However, to be successful, any treatment must affect life-long behavioral changes rather than short-term weight loss. "Yo-yo" dieting, in which weight is repeatedly lost and regained, has been shown to increase a person's likelihood of developing fatal health problems than if the weight had been lost gradually or not lost at all. Behavior-focused treatment should concentrate on:

  • What and how much a person eats. This aspect may involve keeping a food diary and developing a better understanding of the nutritional value and fat content of foods. It may also involve changing grocery-shopping habits (e.g., buying only what is on a prepared list and only going on a certain day), timing of meals (to prevent feelings of hunger, a person may plan frequent, small meals), and actually slowing down the rate at which a person eats.
  • How a person responds to food. This may involve understanding what psychological issues underlie a person's eating habits. For example, one person may binge eat when under stress, while another may always use food as a reward. In recognizing these psychological triggers, an individual can develop alternate coping mechanisms that do not focus on food.
  • How they spend their time. Making activity and exercise an integrated part of everyday life is a key to achieving and maintaining weight loss. Starting slowly and building endurance keeps individuals from becoming discouraged. Varying routines and trying new activities also keeps interest high.

For most individuals who are mildly obese, these behavior modifications entail life-style changes they can make independently while being supervised by a family physician. Other mildly obese persons may seek the help of a commercial weight-loss program (e.g., Weight Watchers). The effectiveness of these programs is difficult to assess, since programs vary widely, drop-out rates are high, and few employ members of the medical community. However, programs that emphasize realistic goals, gradual progress, sensible eating, and exercise can be very helpful and are recommended by many doctors. Programs that promise instant weight loss or feature severely restricted diets are not effective and, in some cases, can be dangerous.

For individuals who are moderately obese, medically supervised behavior modification and weight loss are required. While doctors will put most moderately obese patients on a balanced, low-calorie diet (1200-1500 calories a day), they may recommend that certain individuals follow a very-low-calorie liquid protein diet (400-700 calories) for as long as three months. This therapy, however, should not be confused with commercial liquid protein diets or commercial weight-loss shakes and drinks. Doctors tailor these diets to specific patients, monitor patients carefully, and use them for only a short period of time. In addition to reducing the amount and type of calories consumed by the patient, doctors will recommend professional therapists or psychiatrists who can help the individual effectively change his or her behavior in regard to eating.

For individuals who are severely obese, dietary changes and behavior modification may be accompanied by surgery to reduce or bypass portions of the stomach or small intestine. Although obesity surgery is less risky as of 2003 because of recent innovations in equipment and surgical technique, it is still performed only on patients for whom other strategies have failed and whose obesity seriously threatens their health. Other surgical procedures are not recommended, including liposuction, a purely cosmetic procedure in which a suction device is used to remove fat from beneath the skin, and jaw wiring, which can damage gums and teeth and cause painful muscle spasms.

Appetite-suppressant drugs are sometimes prescribed to aid in weight loss. These drugs work by increasing levels of serotonin or catecholamine, which are brain chemicals that control feelings of fullness. Appetite suppressants, though, are not considered truly effective, since most of the weight lost while taking them is usually regained after stopping them. Also, suppressants containing amphetamines can be potentially abused by patients. While most of the immediate side-effects of these drugs are harmless, the long-term effects of these drugs, in many cases, are unknown. Two drugs, dexfenfluramine hydrochloride (Redux) and fenfluramine (Pondimin) as well as a combination fenfluramine-phentermine (Fen/Phen) drug, were taken off the market when they were shown to cause potentially fatal heart defects. In November 1997, the United States Food and Drug Administration (FDA) approved a new weight-loss drug, sibutramine (Meridia). Available only with a doctor's prescription, Meridia can significantly elevate blood pressure and cause dry mouth, headache, constipation, and insomnia. This medication should not be used by patients with a history of congestive heart failure, heart disease, stroke, or uncontrolled high blood pressure.

Other weight-loss medications available with a doctor's prescription include:

  • diethylpropion (Tenuate, Tenuate dospan)
  • mazindol (Mazanor, Sanorex)
  • phendimetrazine (Bontril, Plegine, Prelu-2, X-Trozine)
  • phentermine (Adipex-P, Fastin, Ionamin, Oby-trim)

Phenylpropanolamine (Acutrim, Dextarim) is the only nonprescription weight-loss drug approved by the FDA These over-the-counter diet aids can boost weight loss by 5%. Combined with diet and exercise and used only with a doctor's approval, prescription anti-obesity medications enable some patients to lose 10% more weight than they otherwise would. Most patients regain lost weight after discontinuing use of either prescription medications or nonprescription weight-loss products.

Prescription medications or over-the-counter weight-loss products can cause:

  • constipation
  • dry mouth
  • headache
  • irritability
  • nausea
  • nervousness
  • sweating

None of them should be used by patients taking monoamine oxidase inhibitors (MAO inhibitors).

Doctors sometimes prescribe fluoxetine (Prozac), an antidepressant that can increase weight loss by about 10%. Weight loss may be temporary and side effects of this medication include diarrhea, fatigue, insomnia, nausea, and thirst. Weight-loss drugs currently being developed or tested include ones that can prevent fat absorption or digestion; reduce the desire for food and prompt the body to burn calories more quickly; and regulate the activity of substances that control eating habits and stimulate overeating.

Alternative treatment

The Chinese herb ephedra (Ephedra sinica ), combined with caffeine, exercise, and a low-fat diet in physician-supervised weight-loss programs, can cause at least a temporary increase in weight loss. However, the large doses of ephedra required to achieve the desired result can also cause:

  • anxiety
  • heart arrhythmias
  • heart attack
  • high blood pressure
  • insomnia
  • irritability
  • nervousness
  • seizures
  • strokes
  • death

Ephedra should not be used by anyone with a history of diabetes, heart disease, or thyroid problems. In fact, an article that appeared in the Journal of the American Medical Association in early 2003 advised against the use of ephedra.

Diuretic herbs, which increase urine production, can cause short-term weight loss but cannot help patients achieve lasting weight control. The body responds to heightened urine output by increasing thirst to replace lost fluids, and patients who use diuretics for an extended period of time eventually start retaining water again anyway. In moderate doses, psyllium, a mucilaginous herb available in bulk-forming laxatives like Metamucil, absorbs fluid and makes patients feel as if they have eaten enough. Red peppers and mustard help patients lose weight more quickly by accelerating the metabolic rate. They also make people more thirsty, so they crave water instead of food. Walnuts contain serotonin, the brain chemical that tells the body it has eaten enough. Dandelion (Taraxacum officinale ) can raise metabolism and counter a desire for sugary foods.

Acupressure and acupuncture can also suppress food cravings. Visualization and meditation can create and reinforce a positive self-image that enhances the patient's determination to lose weight. By improving physical strength, mental concentration, and emotional serenity, yoga can provide the same benefits. Also, patients who play soft, slow music during meals often find that they eat less food but enjoy it more.

Getting the correct ratios of protein, carbohydrates, and good-quality fats can help in weight loss via enhancement of the metabolism. Support groups that are informed about healthy, nutritious, and balanced diets can offer an individual the support he or she needs to maintain this type of eating regimen.

Prognosis

As many as 85% of dieters who do not exercise on a regular basis regain their lost weight within two years. In five years, the figure rises to 90%. Repeatedly losing and regaining weight (yo yo dieting) encourages the body to store fat and may increase a patient's risk of developing heart disease. The primary factor in achieving and maintaining weight loss is a life-long commitment to regular exercise and sensible eating habits.

Prevention

Obesity experts suggest that a key to preventing excess weight gain is monitoring fat consumption rather than counting calories, and the National Cholesterol Education Program maintains that only 30% of calories should be derived from fat. Only one-third of those calories should be contained in saturated fats (the kind of fat found in high concentrations in meat, poultry, and dairy products). Because most people eat more than they think they do, keeping a detailed food diary is a useful way to assess eating habits. Eating three balanced, moderate-portion meals a daywith the main meal at mid-dayis a more effective way to prevent obesity than fasting or crash diets. Exercise increases the metabolic rate by creating muscle, which burns more calories than fat. When regular exercise is combined with regular, healthful meals, calories continue to burn at an accelerated rate for several hours. Finally, encouraging healthful habits in children is a key to preventing childhood obesity and the health problems that follow in adulthood.

New directions in obesity treatment

The rapid rise in the incidence of obesity in the United States since 1990 has prompted researchers to look for new treatments. One approach involves the application of antidiabetes drugs to the treatment of obesity. Metformin (Glucophage), a drug that was approved by the Food and Dug Administration (FDA) in 1994 for the treatment of type 2 diabetes, shows promise in treating obesity associated with insulin resistance.

Another field of obesity research is the study of hormones, particularly leptin, which is produced by fat cells in the body, and ghrelin, which is secreted by cells in the lining of the stomach. Both hormones are known to affect appetite and the body's energy balance. Leptin is also related to reproductive function, while ghrelin stimulates the pituitary gland to release growth hormone. Further studies of these two hormones may lead to the development of new medications to control appetite and food intake.

KEY TERMS

Adipose tissue Fat tissue.

Appetite suppressant Drug that decreases feelings of hunger. Most work by increasing levels of serotonin or catecholamine, chemicals in the brain that control appetite.

Bariatrics The branch of medicine that deals with the prevention and treatment of obesity and related disorders.

Ghrelin A recently discovered peptide hormone secreted by cells in the lining of the stomach. Ghrelin is important in appetite regulation and maintaining the body's energy balance.

Hyperlipidemia Abnormally high levels of lipids in blood plasma.

Hyperplastic obesity Excessive weight gain in childhood, characterized by the creation of new fat cells.

Hypertension High blood pressure.

Hypertrophic obesity Excessive weight gain in adulthood, characterized by expansion of already existing fat cells.

Ideal weight Weight corresponding to the lowest death rate for individuals of a specific height, gender, and age.

Leptin A protein hormone that affects feeding behavior and hunger in humans. At present it is thought that obesity in humans may result in part from insensitivity to leptin.

A third approach to obesity treatment involves research into the social factors that encourage or reinforce weight gain in humans. Researchers are looking at such issues as the advertising and marketing of food products; media stereotypes of obesity; the development of eating disorders in adolescents and adults; and similar questions.

Resources

BOOKS

Beers, Mark H., MD, and Robert Berkow, MD, editors. "Nutritional Disorders: Obesity." Section 1, Chapter 5. In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

Flancbaum, Louis, MD, with Erica Manfred and Deborah Biskin. The Doctor's Guide to Weight Loss Surgery. West Hurley, NY: Fredonia Communications, 2001.

Pi-Sunyer, F. Xavier. "Obesity." In Cecil Textbook of Medicine, edited by Russel L. Cecil, et al. Philadelphia, PA: W. B. Saunders Company, 2000.

PERIODICALS

Aronne, L. J., and K. R. Segal. "Weight Gain in the Treatment of Mood Disorders." Journal of Clinical Psychiatry 64, Supplement 8 (2003): 22-29.

Bell, S. J., and G. K. Goodrick. "A Functional Food Product for the Management of Weight." Critical Reviews in Food Science and Nutrition 42 (March 2002): 163-178.

Brudnak, M. A. "Weight-Loss Drugs and Supplements: Are There Safer Alternatives?" Medical Hypotheses 58 (January 2002): 28-33.

Colquitt, J., A. Clegg, M. Sidhu, and P. Royle. "Surgery for Morbid Obesity." Cochrane Database Systems Review 2003: CD003641.

Espelund, U., T. K. Hansen, H. Orskov, and J. Frystyk. "Assessment of Ghrelin." APMIS Supplementum 109 (2003): 140-145.

Hundal, R. S., and S. E. Inzucchi. "Metformin: New Understandings, New Uses." Drugs 63 (2003): 1879-1894.

Pirozzo, S., C. Summerbell, C. Cameron, and P. Glasziou. "Advice on Low-Fat Diets for Obesity (Cochrane Review)." Cochrane Database Systems Review 2002: CD003640.

Schurgin, S., and R. D. Siegel. "Pharmacotherapy of Obesity: An Update." Nutrition in Clinical Care 6 (January-April 2003): 27-37.

Shekelle, P. G., M. L. Hardy, S. C. Morton, et al. "Efficacy and Safety of Ephedra and Ephedrine for Weight Loss and Athletic Performance: A Meta-Analysis." Journal of the American Medical Association 289 (March 26, 2003): 1537-1545.

Tataranni, P. A. "Treatment of Obesity: Should We Target the Individual or Society?" Current Pharmaceutical Design 9 (2003): 1151-1163.

Veniant, M. M., and C. P. LeBel. "Leptin: From Animals to Humans." Current Pharmaceutical Design 9 (2003): 811-818.

ORGANIZATIONS

American Dietetic Association. (800) 877-1600. www.eatright.org..

American Obesity Association (AOA). 1250 24th Street NW, Suite 300, Washington, DC 20037. (202) 776-7711 or (800) 98-OBESE. www.obesity.org.

American Society for Bariatric Surgery. 7328 West University Avenue, Suite F, Gainesville, FL 32607. (352) 331-4900. www.asbs.org.

American Society of Bariatric Physicians. 5453 East Evans Place, Denver, CO 80222-5234. (303) 770-2526. www.asbp.org.

HCF Nutrition Research Foundation, Inc. P.O. Box 22124, Lexington, KY 40522. (606) 276-3119.

National Institute of Diabetes and Digestive and Kidney Diseases. 31 Center Drive, USC2560, Building 31, Room 9A-04, Bethesda, MD 20892-2560. (301) 496-3583. www.niddk.nih/gov.

National Obesity Research Foundation. Temple University, Weiss Hall 867, Philadelphia, PA 19122.

Weight-Control Information Network. 1 Win Way, Bethesda, MD 20896-3665. (301) 951-1120. www.navigator.tufts.edu/special/win.html.

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Carson-DeWitt, Rosalyn; Frey, Rebecca. "Obesity." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

Carson-DeWitt, Rosalyn; Frey, Rebecca. "Obesity." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1G2-3451601151.html

Carson-DeWitt, Rosalyn; Frey, Rebecca. "Obesity." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3451601151.html

Obesity

OBESITY

OBESITY. Obesity and overweight now affect more than 50 percent of adult Americans. Diabetes mellitus, hypertension, heart disease, gallbladder disease, and some forms of cancer result from obesity. Whether these diseases are yet present or not, the obese individual should be encouraged to lose weight by appropriate methods to reduce the future likelihood that they will develop. Methods of weight loss include diet, nutritional education, self-help groups, and behavioral change. Under some circumstances drugs or surgery may be considered.

Definition and Measurement of Obesity

Obesity and overweight are best defined using the body mass index (BMI). This index is determined by dividing body weight in kilograms by the square of the height in meters: BMI = W/H2. The normal rate for BMI is 18.5 to 25. A BMI between 25 and 30 kg/m2 is defined as over-weight and a BMI above 30 kg/m2 is defined as obesity (Table 1). Visceral fat can be used as an index of central adiposity. An increase in visceral fat reflects central obesity and increases health risks. The waist circumference is used to assess the amount of visceral obesity. A waist circumference in men of 40 inches (102 cm) or more, and in women, of 35 inches (88 cm) or more, is the threshold for defining central obesity (Table 1).

Prevalence of Overweight

More females than males are overweight at any age. The frequency of overweight increases with age to reach a peak at forty-five to fifty-four years in men and at age fifty-five to sixty-four in women. The National Health and Nutrition Examination Survey (NHANES) conducted by the U.S. government (published in 1993) found a BMI of 25 or more in 59.4 percent of men age twenty years or older and in 50.7 percent of women over the age of twenty years. The prevalence of obesity (BMI 30 or more) was 19.5 percent in men and 25.0 percent in women. The incidence of obesity continues to increase dramatically in the United States and elsewhere. A number of factors including age, sex, and physical inactivity influence the amount of body fat.

At birth, the human infant contains about 12 percent body fat. During the first years of life, body fat rises rapidly to reach a peak of about 25 percent by six months of age and then declines to 18 percent over the next ten years. At puberty, there is a significant increase in the percentage of body fat in females and a decrease in males. By age eighteen, males have approximately 15 to 18 percent body fat, and females have 25 to 28 percent. Between

Classification of overweight and obesity by BMI, waist circumference, and associated disease risk
      Disease risk* relative to normal weight and waist circumference
  BMI kg/m 2 Obesity class Men = 102 cm (= 40 in) Women = 88 cm (= 35 in) >102 cm (>40 in) >88 cm (>35 in)
Underweight 18.5  
Normal + 18.524.9  
Overweight 25.029.9   Increased High
Obesity 30.034.9 I High Very High
  35.039.9 II Very High Very High
Extreme Obesity = 40 III Extremely High Extremely High
*Disease risk for type 2 diabetes, hypertension, and CVD.
+Increased waist circumference can also be a marker for increased risk even in persons of normal weight.
Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in AdultsThe Evidence Report. National Institutes of Health.
Obes Res 1998;6 Suppl 2:51S209S.

ages twenty and fifty, the fat content of males approximately doubles and that of females increases by about 50 percent. Total body weight, however, rises by only 10 to 15 percent: fat now accounts for a larger part of the body weight and lean body mass decreases.

Risks Related to Obesity

As the BMI increases, there is a curvilinear rise in excess mortality. This excess mortality rises more rapidly when the BMI is above 30 kg/m2. A BMI over 40 kg/m2 is associated with a further increase in overall risk and for the risk of sudden death. The principal causes of the excess mortality associated with overweight include hypertension, stroke, and other cardiovascular diseases, diabetes mellitus, certain cancers, reproductive disorders, gall-bladder disease, and sudden death.

The insulin-resistant state or metabolic syndrome is strongly associated with visceral fat. It may include consequences such as glucose intolerance or type 2 diabetes mellitus, hypertension, polycystic ovarian syndrome, dyslipidemia (the state of abnormaleither higher or lowervalues for blood fats), and other disorders. These are often responsive to weight loss, especially when this is achieved early and the loss is maintained.

Development of Obesity

Several mechanisms lead to obesity, including neuroendocrine imbalances, particular drugs, diet, reduced energy expenditure, and genetic factors that lead to certain syndromes and predisposition to obesity. Obesity can follow damage to the hypothalamus in the brain, but this is rare. Cushing's disease is somewhat more common and can result in obesity. Treatment should be directed at the cause of the increased formation of adrenal corticosteroids.

Treatment of diabetics with insulin, sulfonylureas, or thiazolidinediones (but not metformin) can increase hunger and food intake, resulting in weight gain. Treatment with some antidepressants, anti-epileptics, and neuroleptics can also increase body weight, as can cyproheptadine (a serotonin antagonist that produces weight gain), probably through effects on the monoamines (including norepinephrine, epinephrine, dopamine, histamine, and serotonin) in the central nervous system.

Eating a high-fat diet and excessive consumption of sugar-sweetened beverages and the prevalence of abundant varieties of food in cafeterias or supermarkets are dietary factors in the development of obesity. Reduced energy expenditure relative to energy intake is another major component. Energy expenditure can be divided into four parts.

An inactive individual at rest burns between 800 and 900 kilocalories during a twenty-four hour period. This rate is lower in females than in males, and declines with age, and could account for much of the increase in fat stores if food intake does not decline similarly. The effect of physical exercise on metabolism is variable but on average is responsible for about one-third of the daily energy expenditure. From a therapeutic point of view this component of energy expenditure is most easily manipulated. Dietary thermogenesis is the energy expenditure that follows the ingestion of a meal. Heat produced by eating may dissipate up to 10 percent of the ingested calories. These thermic effects of food are one type of metabolic "inefficiency" in the body, that is, where dietary calories are not available for "useful" work. In the obese, the thermic effects of food are reduced particularly in individuals with impaired glucose tolerance or diabetes. Acute over-or underfeeding will produce corresponding shifts in overall metabolism, which can be as large as 15 to 20 percent.

Genetic factors can produce some types of obesity that are easily recognized. Among these types of obesity are: (1) the Bardet-Biel syndrome, characterized by retinal degeneration, mental retardation, obesity, polydactyly, and hypogonadism; (2) the Alstrom syndrome, characterized by pigmentary retinopathy, nerve deafness, obesity, and diabetes mellitus; (3) Carpenter syndrome, characterized by acrocephaly (abnormalities in the facial and head bones), mental retardation, hypogonadism, obesity, and preaxial syndactyly (extra fingers or toes on one hand or foot); (4) the Cohen syndrome, characterized by mental retardation, obesity, hypotonia (reduced tone of the muscles, resulting in a "floppy" muscle mass), and characteristic facies (an appearance of the face that is typical of specific genetic diseases); (5) the Prader-Willi syndrome, characterized by hypotonia, mental retardation, hypogonadism, and obesity; and (6) the pro-opiomelanocortin (POMC) syndrome, characterized by defective production of POMC that is recognized as a red-headed fat child with a low plasma cortisol (a value that is below the normal range).

If both parents are obese, about 80 percent of their offspring will be obese. If only one parent is obese, the likelihood of obesity in the offspring falls to less than 10 percent. Studies with identical twins suggest that inheritance accounts for about 70 percent and environmental factors (diet, physical inactivity, or both) account for 30 percent of the variation in body weight. Deficiency of the gene leptin and deficiency of the leptin receptor are rare, but are associated with massive human obesity. Absence of convertase I has also been associated with obesity in one family. The most common defects associated with massive obesity are abnormalities in the melanocortin receptor systemup to 4 percent of massively obese people may have this type of defect.

Evaluation of the Obese Patient

A medical evaluation should include the expected medical history, family history, personal and social history, and review of the systems of the body with a particular focus on the medications that can cause weight gain. A physical examination should include an assessment of the patient's height, weight, waist circumference, blood pressure, and level of health risk due to obesity. Laboratory tests should include a lipid panel, glucose level, chemistry panel for hepatic (liver) function and uric acid, thyroid function testing, and, if indicated a cortisol level.

Evaluating Risk Using the Body Mass Index (BMI)

Individuals with a normal BMI (2025 kg/m2) have little or no risk from obesity. Any individual in this weight range who wishes to lose weight for cosmetic reasons should do so only with conservative methods. Individuals with a BMI of greater than 25 to 29.9 kg/m2 are in the low-risk group for developing heart disease, hypertension, gallbladder disease, and diabetes mellitus associated with obesity. They too should be encouraged to use low-risk treatments, such as caloric restriction and exercise. Individuals with a BMI of 27 to 30 kg/m2 or more who have diseases related to obesity may use adjunctive pharmacotherapy for weight loss.

Individuals with a BMI of 30 to 40 kg/m2, have moderate risk for developing diseases associated with obesity. Diet, drugs, and exercise would all appear to be appropriate forms of treatment. Individuals with significant degrees of excess weight often find exercise difficult. However, exercise is very important in helping to maintain weight loss. The use of weight loss medications, as an adjunct to treatment, may also be useful in this group. Individuals who have a BMI above 40 kg/m2 have a high risk of developing diseases associated with their obesity. Moderate to severe restriction of calories is the first line of treatment, but for some of these patients surgery may be advisable.

Treatment of Obesity

Any diet must reduce an individual's caloric intake below daily caloric expenditure if it is to be successful. This requires an assessment of caloric requirements, by estimating caloric expenditure from desirable weight tables; for men, multiply desirable weight by 30 to 35 kilocalories/kilogram, (1416 kilocalories/lb.); for women, multiply desirable weight by 25 to 30 kilocalories/kilogram (1214 kilocalories/lb.). After assessing caloric requirements, a reasonable calorie deficit can be prescribed. A caloric deficit of 500 kilocalories/day (3,500 kilocalories/week) will produce the loss of approximately one lb. (0.45 kilograms) of fat tissue each week. Table 2 gives a list of diets divided into different levels of energy.

The very low calorie diet (below 800 kilocalories) was developed to facilitate the rate of weight loss since lower energy intake should lead to greater energy deficit. In free living people, however, diets with 400 kilocalories/day have not produced greater weight loss than those with 800 kilocalories/day, suggesting either that they are harder to adhere to or that there is an adaptation in energy expenditure. In either case, these diets should only be used under appropriate medical supervision.

Characterization of diets by composition
Type of diet Calories Fat g (%) Carbohydrate g (%) Protein g (%)
Typical American 2,200 85 (35) 274 (50) 82 (15)
High-fat, low carbohydrate 1,400 94 (60) 35 (10) 105 (30)
Moderate-fat 1,450 40 (25) 218 (60) 54 (15)
Low & very low fat 1,450 1624 (1015) 235271 (6575) 5472 (1520)

Types of diets. There are several types of diets with more than 800 kilocalories/day that usually have more than 1,200 kilocalories/day. They can be divided into several categories. These categories are based on the relative proportion of macronutrients included in the diet and whether they use special foods. For all diets it must be true that they reduce the calorie intake to produce a negative energy balance. Low-carbohydrate diets are touted because they produce ketosis (a state of increased ketones associated with diabetes and fasting) and allow you to eat all of the protein and fat you want. This ends up reducing total calorie intake to about 1,500 kilocalories/day. Since these diets generally have carbohydrate levels below 50 g./day they are ketogenic and can be monitored clinically by the appearance of ketones in the urine. They vary in the level of fiber that is employed. The Atkins diet has low fiber levels, the Sugar Busters diet higher fiber levels.

Low-fat diets recommend fat intake in the range of 10 to 20 percent of calories. The higher carbohydrate increases fiber intake. These diets were developed in a setting designed to reverse the atherosclerotic plaques associated with risks for heart disease, but because of the high fiber content they were often associated with weight loss. Moderate fat levels with higher carbohydrates are characteristic of many widely recommended "healthy diets." For weight loss, the New York Health Department recommends the Prudent Diet, which has stood the test of time.

The portion-controlled diet makes use of prepared foods that have a narrow range of calories. This includes liquid or powdered drinks as well as frozen or canned entrees that have about 300 kilocalories/meal. These can be combined conveniently and thus removes the problem of counting calories from the individual. A number of popular diets focus on a single food, and although nutritionally unbalanced, they are simple to follow and the monotony of single items tends to limit food intake.

Food Guide Pyramid. The Food Guide Pyramid provides an approach to evaluating the quality of your diet. At the bottom of the pyramid are the grains, beans, and starchy vegetables that provide vitamins, minerals, fiber, and energy; six or more servings are recommended. On the next level are the vegetables (35 servings) and the fruits (34 servings). On the third level are the meats, fish, poultry, and nuts (23 servings) along with the milk and yogurt (23 servings). At the top are the fats, sweets, and alcohol. Reducing the number of servings proportionally will provide you with a calorie-reduced diet. Most important for the dieter, however, is to sharply reduce the fats and sugar at the top of the pyramid and to reduce or eliminate alcoholic beverages. Not only do alcoholic beverages have calories, their consumption tends to reduce the individual's control in selecting the quality and quantity of foods to eat.

Changing behavioral patterns of eating. The basic principles of behavioral approaches for obesity can be summarized under the ABCs of eating.

  • The A stands for antecedent. If one looks at eating as the response to events in the environment, then the antecedent events are those that trigger eating.
  • The B stands for the behavior of eating. This includes among other things the place, the rate, and the frequency with which an individual eats. If the act of eating can be focused at one place with one plate and place setting it can help to provide control over eating.
  • The C is the consequence of the eating. The feelings an individual has about eating can be altered, and rewards for changing eating patterns can be instituted.

Exercise and physical activity. The only part of energy expenditure that is amenable to significant manipulation is physical activity. During sleep, the lowest level of activity, approximately 0.8 kilocalories/minute is consumed. Thus, if an individual sleeps for an entire 24 hours, approximately 1,150 calories will be expended. Reclining increases this level to approximately 1.0-1.4 kilocalories/minute. Obese and diabetic patients should be encouraged to increase their physical activity for two reasons: First, it consumes calories, but second, and more important, exercise increases glucose utilization and may improve insulin sensitivity.

Drug treatment of obesity. Only a few drugs have been approved by the Food and Drug Administration for treatment of obesity. Studies following individuals who have used these drugs for two years have been published for sibutramine (Meridia) and orlistat (Xenical). Weight-loss drugs should be reserved for patients with moderate-or high-risk obesity (BMI >30 kg/m2) or a BMI above 27 if they have other significant diseases related to obesity. They should be considered for the patient who has failed to lose weight with other methods. Herbal products containing ephedra and an herbal source of caffeine can also produce weight loss when used in accordance with the package instructions.

Surgery. Gastric operations reduce the size of or bypass the stomach, but should be reserved for people with a BMI above 40 or when recommended by a physician.

The Obese Child

Estimates of the prevalence of obesity in children range from 3 to 15 percent. This figure has been rising more rapidly than in the rest of the population. The appearance of obesity in childhood and particularly adolescence is important because it most often persists into adult life. It may be a precursor to the appearance of type 2 diabetes in adolescents. The possibility of treatment should be considered for children who are above the seventy-fifth percentile of weight for height, and might be encouraged for those who are above the ninety-fifth percentile of weight for height. The treatment of prepubertal children should probably involve both parents and child since at this age the principal control of food availability is in the hands of the parents. For adolescents, however, it may be better to separate patient and parents, since the interaction between these groups may be part of the problem. Where growth has not reached its fullest extent, dietary restriction should attempt to reduce further weight gain. Severe caloric restriction and the use of appetite-suppressing drugs may slow height growth. For both children and adolescents, involvement in a regular exercise program is probably the first line of treatment.

See also Anorexia, Bulimia; Body; Body Composition; Caloric Intake; Eating: Anatomy and Physiology of Eating; Fasting and Abstinence; Fats; Fiber, Dietary; Hunger, Physiology of.

BIBLIOGRAPHY

Bessesen, D. H., and R. Kushner. Evaluation and Management of Obesity. Center for Obesity Research and Education. Philadelphia: Hanley and Belfus, 2002.

Bray, George A. Contemporary Diagnosis and Management of Obesity. Newtown, Pa.: Handbooks in Health Care, 1998.

National Heart, Lung, and Blood Institute (NHLBI). Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. Bethesda, Md., 1998.

Yanovski, J., and S. Z. Yanovski. "Obesity." New England Journal of Medicine 346, no. 8 (21 February 2002): 591602.

George Bray

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Bray, George. "Obesity." Encyclopedia of Food and Culture. 2003. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

Bray, George. "Obesity." Encyclopedia of Food and Culture. 2003. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1G2-3403400453.html

Bray, George. "Obesity." Encyclopedia of Food and Culture. 2003. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3403400453.html

Obesity

Obesity

Definition

Obesity is an abnormal accumulation of body fat, usually 20% or more over an individual's ideal body weight. Obesity is associated with increased risk of illness, disability, and death.

The branch of medicine that deals with the study and treatment of obesity is known as bariatrics. As obesity has become a major health problem in the United States, bariatrics has become a separate medical and surgical specialty.

Description

Obesity traditionally has been defined as body weight at least 20% above the weight corresponding to the lowest death rate for individuals of a specific height, sex, and age (designated as the ideal weight). Twenty to forty percent over ideal weight is considered mildly obese; 40100% over ideal weight is considered moderately obese; and 100% over ideal weight is considered severely, or morbidly, obese. According to some estimates, approximately 25% of the United States population can be considered obese, 4 million of whom are morbidly obese. Other studies state that over 50% of American adults are obese, based on body mass index (BMI) measurements. Excessive weight can result in many serious, and potentially deadly, health problems, including hypertension , Type II diabetes mellitus (non-insulin dependent diabetes), increased risk for coronary disease, increased unexplained heart attack , hyperlipidemia, infertility , and a higher prevalence of colon, prostate, endometrial, and possibly, breast cancer . Approximately 300,000 deaths a year are attributed to obesity, prompting leaders in public health, such as former Surgeon General C. Everett Koop to label obesity "the second leading cause of preventable deaths in the United States."

Causes & symptoms

The mechanism for excessive weight gain is clearmore calories are consumed than the body burns, and the excess calories are stored as fat (adipose) tissue. However, the exact cause is not as clear and likely arises from a complex combination of factors. Genetic factors significantly influence how the body regulates appetite and the rate at which it turns food into energy (metabolic rate). Studies of adoptees confirm this relationship. The majority of adoptees followed a pattern of weight gain that more closely resembled that of their birth parents than their adoptive parents. A genetic predisposition to weight gain, however, does not automatically mean that a person will be obese. Eating habits and patterns of physical activity also play a significant role in the amount of weight a person gains.

Some recent studies have indicated that the amount of fat in a person's diet may have a greater impact on weight than the number of calories the food contains. Carbohydrates like cereals, breads, fruits and vegetables, and protein (fish, lean meat, turkey breast, skim milk) are converted to fuel almost as soon as they are consumed. Most fat calories are immediately stored in fat cells, which add to the body's weight and girth as they expand and multiply. There is continuing research on the theory that fat is metabolized as fuel and energy and that only excess carbohydrates are converted to stored fat. Current evidence shows that weight gain comes mostly from total calories consumed, rather than from the amount of carbohydrates. A study published in 2002 found that low-fat diets are no more effective in weight reduction programs than low-calorie diets. At any rate, a sedentary life-style, particularly prevalent in affluent societies like the United States, can contribute to weight gain. Psychological factors, such as depression and low self-esteem may, in some cases, also play a role in weight gain.

At what stage of life a person becomes obese can effect his or her ability to lose weight. In childhood, excess calories are converted into new fat cells (hyperplastic obesity), while excess calories consumed in adulthood only serve to expand existing fat cells (hypertrophic obesity). Since dieting and exercise can only reduce the size of fat cells, not eliminate them, persons who were obese as children can have great difficulty losing weight, since they may have up to five times as many fat cells as someone who became overweight as an adult.

Obesity can also be a side effect of certain disorders and conditions, including:

  • Cushing's syndrome, a disorder involving the excessive release of the hormone cortisol
  • hypothyroidism, a condition caused by an underactive thyroid gland
  • neurologic disturbances, such as damage to the hypothalamus, a structure located deep within the brain that helps regulate appetite
  • consumption of certain drugs, such as steroids, antipsychotic medications, or antidepressants

The major symptoms of obesity are excessive weight gain and the presence of large amounts of fatty tissue. Obesity can also give rise to several secondary conditions, including:

  • arthritis and other orthopedic problems, such as lower back pain
  • heartburn
  • high cholesterol levels
  • high blood pressure
  • menstrual irregularities or cessation of menstruation (amenorhhea)
  • shortness of breath that can be incapacitating
  • skin disorders, arising from the bacterial breakdown of sweat and cellular material in thick folds of skin or from increased friction between folds

Diagnosis

Dignosis of obesity is made by observation and by comparing the patient's weight to ideal weight charts. Many doctors and obesity researchers refer to the body mass index (BMI), which uses a height-weight relationship to calculate an individual's ideal weight and personal risk of developing obesity-related health problems. Physicians may also obtain direct measurements of an individual's body fat content by using calipers to measure skin-fold thickness at the back of the upper arm and other sites. The most accurate means of measuring body fat content involves immersing a person in water and measuring relative displacement; however, this method is very impractical and is usually only used in scientific studies requiring very specific assessments. Women whose body fat exceeds 30% and men whose body fat exceeds 25% are generally considered obese.

Doctors may also note how a person carries excess weight on his or her body. Studies have shown that this factor may indicate whether or not an individual has a predisposition to develop certain diseases or conditions that may accompany obesity. "Apple-shaped" individuals who store most of their weight around the waist and abdomen are at greater risk for cancer, heart disease, stroke , and diabetes than "pear-shaped" people whose extra pounds settle primarily in their hips and thighs.

Treatment

Treatment of obesity depends primarily on the degree of a person's overweight and his or her overall health. However, to be successful, any treatment must affect life-long behavioral changes rather than short-term weight loss. "Yo-yo" dieting, in which weight is repeatedly lost and regained, has been shown to increase a person's likelihood of developing fatal health problems than if the weight had been lost gradually or not lost at all. Behavior-focused treatment should concentrate on:

  • What a person eats and how much. This aspect may involve keeping a food diary and developing a better understanding of the nutritional value and fat content of foods. It may also involve changing grocery shopping habits (e.g. buying only what is on a prepared list and going only on a certain day), timing of meals (to prevent feelings of hunger, a person may plan frequent small meals), and actually slowing down the rate at which a person eats.
  • How a person responds to food. This may involve understanding what psychological issues underlie a person's eating habits. For example, one person may binge eat when under stress , while another may always use food as a reward. In recognizing these psychological triggers, an individual can develop alternate coping mechanisms that do not focus on food.
  • How people spend their time. Making activity and exercise an integral part of everyday life is a key to achieving and maintaining weight loss. Starting slowly and building endurance keeps individuals from becoming discouraged. Varying routines and trying new activities also keeps interest high.

For most who are mildly obese, these behavior modifications entail lifestyle changes they can make independently while being supervised by a family physician. Other mildly obese persons may seek the help of a commercial weight loss program (e.g. Weight Watchers). The effectiveness of these programs is difficult to assess, since programs vary widely, dropout rates are high, and few employ members of the medical community. However, programs that emphasize realistic goals, gradual progress, sensible eating, and exercise can be very helpful and are recommended by many doctors. Programs that promise instant weight loss or feature severely restricted diets are not effective and, in some cases, can be dangerous.

For individuals who are moderately obese, medically supervised behavior modification and weight loss are required. While doctors will put most moderately obese patients on a balanced low-calorie diet (12001500 calories a day), they may recommend that certain individuals follow a very low-calorie liquid protein diet (400700 calories) for as long as three months. This therapy, however, should not be confused with commercial liquid-protein diets or commercial weight-loss shakes and drinks. Doctors tailor these diets to specific patients, monitor patients carefully, and use them for only a short period of time. In addition to reducing the amount and type of calories consumed by the patient, doctors will recommend professional therapists or psychiatrists who can help the individual effectively change his or her behavior in regard to eating.

The Chinese herb ephedra (Ephedra sinica, or ma huang), combined with exercise and a low-fat diet in physician-supervised weight-loss programs, can cause at least a temporary increase in weight loss. However, the large doses of ephedra required to achieve the desired result can also cause:

  • anxiety
  • heart arrhythmias
  • heart attack
  • high blood pressure
  • insomnia
  • irritability
  • nervousness
  • seizures
  • strokes
  • death

Ephedra should not be used by anyone with a history of diabetes, heart disease, or thyroid problems. It is not recommended for long-term use, and can cause serious medical or psychiatric problems if used too long. An article that appeared in the Journal of the American Medical Association in early 2003 advised against the use of ephedra.

Diuretic herbs, which increase urine production, can cause short-term weight loss but cannot help patients achieve lasting weight control. The body responds to heightened urine output by increasing thirst to replace lost fluids, and patients who use diuretics for an extended period of time eventually start retaining water again anyway. In moderate doses, psyllium , a mucilaginous herb available in bulk-forming laxatives like Metamucil, absorbs fluid and makes patients feel as if they have eaten enough. Red peppers and mustard help patients lose weight more quickly by accelerating the metabolic rate. They also make people more thirsty, so they crave water instead of food. Walnuts contain serotonin, the brain chemical that tells the body it has eaten enough. Dandelion (Taraxacum officinale ) can raise metabolism and counter a desire for sugary foods.

The amino acid 5-hydroxytryptophan, or 5-HTP , which is extracted from the seeds of the Griffonia simplicifolia plant, is thought to increase serotonin levels in the brain. Serotonin is a neurotransmitter, or brain chemical, that regulates mood and thus can be linked to mood-related eating behaviors. When physical and mental stress reduces serotonin levels in the body, 5-HTP may be helpful in regulating mood by boosting serotonin levels. Individuals should consult with their healthcare professional before taking 5-HTP, as the amino acid may interact with other medications and can have potentially serious side effects.

Acupressure and acupuncture can also suppress food cravings. Visualization and meditation can create and reinforce a positive self-image that enhances the patient's determination to lose weight. By improving physical strength, mental concentration, and emotional serenity, yoga can provide the same benefits. Also, patients who play soft, slow music during meals often find that they eat less food but enjoy it more.

Eating the correct ratio of protein, carbohydrates, and good-quality fats can help in weight loss via enhancement of metabolism. Support groups and self-help groups such as Overeaters Anonymous and TOPS (Taking Off Pounds Sensibly) that are informed about healthy, nutritious, and balanced diets can offer an individual the support he or she needs to maintain this type of eating regimen.

Allopathic treatment

For individuals who are severely obese, dietary changes and behavior modification may be accompanied by surgery to reduce or bypass portions of the stomach or small intestine. The risks of obesity surgery have declined in recent years, but it is still only performed on patients for whom other strategies have failed and whose obesity seriously threatens their health. Other surgical procedures are not recommended, including liposuction, a purely cosmetic procedure in which a suction device is used to remove fat from beneath the skin, and jaw wiring, which can damage gums and teeth and cause painful muscle spasms.

A newer approach to weight loss is the development of functional foods, which are food products that incorporate natural compounds shown to help in weight loss programs. These compounds include carbohydrates with a low glycemic index, which help to suppress appetite; green tea extract, which increases the body's energy expenditure; and chromium , which encourages the body to burn stored fat rather than lean muscle tissue. Functional food products are currently undergoing clinical testing.

Appetite suppressant drugs are sometimes prescribed to aid in weight loss. These drugs work by increasing levels of serotonin or catecholamine, which are brain chemicals that control moods and feelings of fullness. Appetite suppressants, though, are not considered truly effective, since most of the weight lost while taking them is usually regained after stopping. Also, suppressants containing amphetamines can be potentially abused by patients. While most of the immediate side effects of these drugs are harmless, the long-term effects in many cases, are unknown. Two drugs, dexfenfluramine hydrochloride (Redux) and fenfluramine (Pondimin) as well as a combination fenfluramine-phentermine (Fen/Phen) drug, were taken off the market when they were shown to cause potentially fatal heart defects. In 1999, the United States Food and Drug Administration (FDA) approved a new prescription weight loss drug, Orlistat. Unlike other anti-obesity drugs that act as appetite suppressants, Orlistat encourages weight loss by inhibiting the body's ability to absorb dietary fat. The drug can cause side effects of abdominal cramping, gas , and diarrhea .

Other weight-loss medications available with a doctor's prescription include:

  • Sibutramine (Meridia)
  • Diethylpropion (Tenuate, Tenuate Dospan)
  • Mazindol (Mazanor, Sanorex)
  • Phendimetrazine (Bontril, Prelu-2)
  • Phentermine (Adipex-P, Fastin, Ionamin, Oby-Cap)

Phenylpropanolamine (Acutrim, Dextarim) is the only nonprescription weight-loss drug approved by the FDA. These over-the-counter diet aids can boost weight loss by 5%. Combined with diet and exercise and used only with a doctor's approval, prescription anti-obesity medications enable some patients to lose 10% more weight than they otherwise would. Most patients regain lost weight after discontinuing use of either prescription medications or nonprescription weight-loss products.

Prescription medications or over-the-counter weight loss products can cause:

  • constipation
  • dry mouth
  • headache
  • irritability
  • nausea
  • nervousness
  • sweating

None of the weight loss drugs should be used by patients taking monoamine oxidate inhibitors (MAO inhibitors).

Doctors sometimes prescribe fluoxetine (Prozac), an antidepressant that can increase weight loss by about 10%. Weight loss may be temporary and side effects of this medication include diarrhea, fatigue , insomnia, nausea, and thirst. Weight loss drugs currently being developed or tested include ones that can prevent fat absorption or digestion, reduce the desire for food and prompt the body to burn calories more quickly, and regulate the activity of substances that control eating habits and stimulate overeating.

Expected results

As many as 85% of dieters who do not exercise on a regular basis regain their lost weight within two years. In five years, the figure rises to 90%. Repeatedly losing and regaining weight (yo-yo dieting) encourages the body to store fat and may increase a patient's risk of developing heart disease. The primary factor in achieving and maintaining weight loss is a lifelong commitment to regular exercise and sensible eating habits.

Prevention

Obesity experts suggest that a key to preventing excess weight gain is monitoring fat consumption rather than counting calories, and the National Cholesterol Education Program maintains that only 30% of calories should be derived from fat. Only one-third of those calories should be contained in saturated fats (the kind of fat found in high concentrations in meat, poultry, and dairy products). Because most people eat more than they think they do, keeping a detailed food diary is a useful way to assess eating habits. Eating three balanced, moderate-portion meals a daywith the main meal at mid-dayis a more effective way to prevent obesity than fasting or crash diets. Exercise increases the metabolic rate by creating muscle, which burns more calories than fat. When regular exercise is combined with regular, healthful meals, calories continue to burn at an accelerated rate for several hours. Finally, encouraging healthful habits in children is a key to preventing childhood obesity and the health problems that follow in adulthood.

New directions in obesity treatment

The rapid rise in the incidence of obesity in the United States since 1990 has prompted researchers to look for new treatments. One approach involves the application of antidiabetes drugs to the treatment of obesity. Metformin (Glucophage), a drug that was approved by the Food and Dug Administration (FDA) in 1994 for the treatment of type 2 diabetes, shows promise in treating obesity associated with insulin resistance .

Another field of obesity research is the study of hormones, particularly leptin, which is produced by fat cells in the body, and ghrelin, which is secreted by cells in the lining of the stomach. Both hormones are known to affect appetite and the body's energy balance. Leptin is also related to reproductive function, while ghrelin stimulates the pituitary gland to release growth hormone. Further studies of these two hormones may lead to the development of new medications to control appetite and food intake.

A third approach to obesity treatment involves research into the social factors that encourage or reinforce weight gain in humans. Researchers are looking at such issues as the advertising and marketing of food products; media stereotypes of obesity; the development of eating disorders in adolescents and adults; and similar questions.

Resources

BOOKS

Ackerman, Norman. 5-HTP: The Natural Way to Overcome Depression, Obesity, and Insomnia. New York: Bantam Books, 1999.

Flancbaum, Louis, MD, with Erica Manfred and Deborah Biskin. The Doctor's Guide to Weight Loss Surgery. West Hurley, NY: Fredonia Communications, 2001.

Harris, Dan R., ed. Diet and Nutrition Sourcebook. Detroit, MI: Omnigraphics, 1996.

"Nutritional Disorders: Obesity." Section 1, Chapter 5 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

PERIODICALS

Aronne, L. J., and K. R. Segal. "Weight Gain in the Treatment of Mood Disorders." Journal of Clinical Psychiatry 64 (2003 Supplement 8): 2229.

Bell, S. J., and G. K. Goodrick. "A Functional Food Product for the Management of Weight." Critical Reviews in Food Science and Nutrition 42 (March 2002): 163178.

Brudnak, M. A. "Weight-Loss Drugs and Supplements: Are There Safer Alternatives?" Medical Hypotheses 58 (January 2002): 2833.

Colquitt, J., A. Clegg, M. Sidhu, and P. Royle. "Surgery for Morbid Obesity." Cochrane Database Systems Review 2003: CD003641.

Espelund, U., T. K. Hansen, H. Orskov, and J. Frystyk. "Assessment of Ghrelin." APMIS Supplementum 109 (2003): 140145.

Hundal, R. S., and S. E. Inzucchi. "Metformin: New Understandings, New Uses." Drugs 63 (2003): 18791894.

Pirozzo, S., C. Summerbell, C. Cameron, and P. Glasziou. "Advice on Low-Fat Diets for Obesity (Cochrane Review)." Cochrane Database Systems Review 2002: CD003640.

Schurgin, S., and R. D. Siegel. "Pharmacotherapy of Obesity: An Update." Nutrition in Clinical Care 6 (January-April 2003): 2737.

Shekelle, P. G., M. L. Hardy, S. C. Morton, et al. "Efficacy and Safety of Ephedra and Ephedrine for Weight Loss and Athletic Performance: A Meta-Analysis." Journal of the American Medical Association 289 (March 26, 2003): 15371545.

Tataranni, P. A. "Treatment of Obesity: Should We Target the Individual or Society?" Current Pharmaceutical Design 9 (2003): 11511163.

Veniant, M. M., and C. P. LeBel. "Leptin: From Animals to Humans." Current Pharmaceutical Design 9 (2003): 811818.

ORGANIZATIONS

American Dietetic Association. (800) 877-1600. <www.eatright.org.>.

American Obesity Association (AOA). 1250 24th Street NW, Suite 300, Washington, DC 20037. (202) 776-7711 or (800) 98-OBESE. <www.obesity.org>.

American Society of Bariatric Physicians. 5453 East Evans Place, Denver, CO 80222-5234. (303) 770-2526. <www.asbp.org>.

American Society for Bariatric Surgery. 7328 West University Avenue, Suite F, Gainesville, FL 32607. (352) 331-4900. <www.asbs.org>.

North American Association for the Study of Obesity. 8630 Fenton St., Suite 412, Silver Spring, MD, 20910. (301) 563-6526. <www.naaso.org.>.

Overeaters Anonymous. P.O. Box 44020, Rio Rancho, New Mexico, 87174-4020. (505) 891-2664. <www.overeatersanonymous.org.>.

Weight-control Information Network (WIN). 1 WIN Way, Bethesda, MD 20892-3665. (202) 828-1025 or (877) 946-4627.

Paula Ford-Martin

Rebecca J. Frey, PhD

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Ford-Martin, Paula; Frey, Rebecca. "Obesity." Gale Encyclopedia of Alternative Medicine. 2005. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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Ford-Martin, Paula; Frey, Rebecca. "Obesity." Gale Encyclopedia of Alternative Medicine. 2005. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3435100574.html

Obesity

Obesity

Definition

Obesity is the condition of having an excessive accumulation of fat in the body, resulting in a body weight more than 20% above the average for height, age, sex, and body type, and in elevated risk of disability, illness, and death.

Description

The human body is composed of bone, muscle, specialized organ tissues, and fat. Together, all of these tissues comprise the total body mass, which is measured in pounds. Fat, or adipose tissue, is a combination of essential fat (an energy source for the normal physiologic function of cells and organs) and storage fat (a reserve supply of energy for future needs). When the amount of energy consumed as food exceeds the amount of energy expended in the normal maintenance of life processes and in physical activity, storage fat accumulates in excessive amounts. Essential fat is tucked in and around internal organs, and is an important building block of all cells in the body. Storage fat accumulates in the chest and abdomen, and, in much greater volume, under the skin.

Causes and symptoms

The human body was designed for life forty thousand years ago, when the ability to store energy in times of plenty meant the difference between life and death during famine. This protective mechanism is a source of trouble when food, in unlimited quantities, is readily available,. This is evident in the increasing prevalence of obesity in modern times, particularly in Western cultures. While obesity is just an exaggeration of a normal body, the storage of energy for future is properly classified as a health problem. This is because excessive amounts of storage fat may interfere with the normal physiology of the body. Obesity is directly related to the increasing prevalence of Type II diabetes in American society and for the appearance of Type II diabetes in children, previously a rarity. Because obesity promotes degenerative disease of joints and heart and blood vessels, it increases the need for some surgical procedures. At the same time, surgical complication rates are higher in obese patients. Obesity contributes to fatigue , high blood pressure, menstrual disorders, infertility, digestive complaints, low levels of physical fitness, and to the development of some cancers. The social costs of obesity that include decreased productivity, discrimination, depression, and low self-esteem, are less easily described and measured. Worldwide, obesity has reached epidemic proportions in the last thirty years, affecting both sexes and all ethnic, age, and socioeconomic groups. More than 50% of adults in the United States currently fall into overweight or obese classifications, and 22% of preschool children are classified as overweight. The increasing prevalence of obesity and diabetes in children and young adults heralds spiraling health care costs in the near future.

Because obesity reflects an imbalance between the amount of energy taken into the body in the form of food and the amount of energy expended in metabolism and physical activity, and because eating is an activity that involves choice and volition, obesity is classified by the Health Care Financing Administration (HCFA) as a "behavior" rather than as a disease. In recent years, following a pattern established in other behavioral problems such as alcoholism, researchers have attempted to establish a biologic basis for the development of obesity. They have succeeded in identifying many markers of the biochemical mechanisms that appear to be involved in feedback loops that control energy balance. However, much of the information is extrapolated from experimental work in rodents. Leptin, a hormone produced in fat cells is an example of such a marker. Leptin excited a great deal of hope as a potential treatment of obesity, but, as with many other laboratory discoveries, the hormone has proved far more complex and less easily understood in humans. Research to date indicates that obesity is the end product of numerous contributing factors, including genetics, hormonal influences, behavioral tendencies, medication effects, and the surrounding society. But the rapid and widespread increase in obesity in the last thirty years reflects changes in activity patterns and in eating habits, not a change in the human genetic pool or in physiology.

Diagnosis

There are two methods of diagnosing obesity. The first method is inspectionwhereby an excessive amount of storage fat is usually noticeable upon visual inspection. The second method is inference of body fat content, obtained from body measurements such as weight or skinfold thickness, and comparison with charts of similar measurements in broad populations. The determination of obesity is based on the amount of variance from "normal," a value that comes from statistics on death rates in people with similar measurements. Calculations such as the body mass index (BMI) use a height-weight relationship to calculate an individual's ideal weight and personal risk of developing obesityrelated health problems. An individual with a BMI of25.929, for example, is considered overweight; a person with a BMI over 30 is classified as obese.

The problem with using weight as a measure of obesity is the fact that weight does not accurately represent body composition. A heavily-muscled football player may weigh far more than a sedentary man of similar height, but have significantly less body fat. Chronic dieters, who have lost significant muscle mass during periods of caloric deprivation, may look slim and weigh little, but have elevated body fat percentages. The most accurate means of estimating body fat content involves weighing a person two ways: First, the person is weighed under water. The difference between dry and underwater weight is calculated to obtain the volume of water displaced by the mass of the body. While this method is impractical, it has the advantage of determining body composition most accurately, and is the truest reflection of the actual percentage of body mass that is fat. Women whose body fat exceeds 30% of total body mass and men whose body fat exceeds 25% are generally considered obese.

The pattern of fat distribution on the body may indicate whether an individual has a predisposition to develop certain diseases or conditions that may accompany obesity. "Apple-shaped" individuals who store most of their weight around the waist and abdomen are at greater risk for cancer, heart disease, stroke , and diabetes than "pear-shaped" people, whose extra pounds settle primarily on their hips and thighs.

Treatment

Since obesity develops when intake of the food required to produce energy exceeds the amount of energy used in metabolism and in physical activity, the treatment of obesity must alter one or both aspects of the energy stream. The options are to decrease energy intake or to increase energy output, or both. However, the problem does not yield rapidly to either method. Storage fat is meant to protect its bearer from starvation when food is unavailable, and before fat is tapped for energy. In the face of decreased intake of food, the body breaks down muscle to construct the sugar it needs to feed the brain . Much of the early weight loss on a very low calorie diet represents loss of muscle tissue rather than loss of fat. Similarly, fat is not easy to access as fuel for exercise. A person of normal weight (according to one of the charts as described above) has enough body fat to fuel the muscles for days of continuous running, but will collapse long before burning any significant amount fat stored by the body.

When obesity develops in childhood, the total number of fat cells increases (hyperplastic obesity), whereas in adulthood, it is the total amount of fat in each cell that increases (hypertrophic obesity). Decreasing the amount of energy (food) consumed or increasing the amount of energy expended cannot change the number of fat cells already present. These actions can only reduce the amount of fat in each cell, and only if the process is slow and steadyas it was in reverse, when the excess fat accumulated. Prevention, as in so many problems, is far superior to any available treatment of obesity.

The strategy for weight loss in obese patients is first to change behavior; then, it is to decrease the expectation of rapid change. Behavioral treatment is goal-directed, process-oriented, and relies heavily on self-monitoring. Emphasis is on:

  • Food intake: The potential energy provided by food is measured in calories, and the capacity of a certain type and amount of food to provide energy is called its caloric content. Keeping a food diary and developing a better understanding of the nutritional value and fat content of foods, changing grocery-shopping habits, paying attention to timing and appearance of meals, and slowing the speed of eating all help to modify food intake.
  • Response to food: The body is capable of matching energy intake and output perfectly, but, in obese individuals, food intake is often unrelated from physiologic cues. Eating occurs for many reasons other than hunger. What psychological issues underlie the eating habits? Does stress cause binge eating ? Is food seen as a reward? Recognition of psychological triggers is necessary for the development of alternate coping mechanisms that do not focus on food.
  • Time usage: The body is suited for an ancient world in which physical activity was a necessity. In the modern world, physical activity must be a conscious choice. Making activity and exercise an integrated part of everyday life is a key to achieving and maintaining weight loss. Sedentary and overweight individuals have to reclaim slowly the endurance that is natural by managing their time to allow for gradual increases in both programmed and conscious lifestyle activity.

Behavior modification

For most individuals who are mildly obese, behavior modifications entail life-style changes they can make independently if they have access to accurate information and have reached the point of readiness to make a serious commitment to losing weight. A family physician's evaluation is helpful, particularly in regard to exercise capacity and nutritional requirements. Commercial weight-loss programs may be helpful for some mildly obese individuals, but they are of varying quality. A good program emphasizes realistic goals, gradual progress, sensible and balanced eating, and increased physical activity; it is often recommended by physicians. Programs that promise instant weight loss or feature severe restrictions in types and amounts of food are not effective, and, in some cases, can be dangerous.

For individuals who are moderately obese, medically supervised behavior modification and weight loss are more likely to be effective than an independent program. A realistic goal is loss of 10% of current weight over a six-month period. While doctors put most moderately obese patients on balanced, low-calorie diets (1,2001,500 calories a day), occasionally they recommend a very low calorie liquid protein diet (400700 calories), with supplementation of vitamins and minerals, for as long as three months. Professional help with behavior modification is of paramount importance in such cases; without changing eating habits and exercise patterns, weight lost will be regained quickly.

Surgery

For individuals who are morbidly obese, surgery to bypass portions of the stomach and small intestine may at times be the only effective means of producing sustained and significant weight loss. Such obesity surgery, however, can be risky, and it is performed only on patients for whom other strategies have failed and whose obesity seriously threatens health. Liposuction is a purely cosmetic procedure in which a suction device is used to remove fat from beneath the skin, and has no place in the treatment of obesity.

Medications

Most of the current research on obesity is aimed at identifying biochemical pathways that will be amenable to intervention with drug treatments. These medications would be specifically tailored to interfere with the energy cycles to facilitate weight loss. As of 2002, there are two major classes of drugs that are approved for the treatment of obesity by the U.S. Food and Drug Administration (FDA). History of the field is littered with drugs that have failed or that have caused serious side effects. Appetite suppressant drugs such as Dexatrim and Meridia (sibutramine) change the amounts of some neurotransmitters in the brain. These chemical changes result in decreased appetite, but only in the presence of the drug. Digestive inhibitors such as Orlistat (Xenical) are drugs that interfere with the breakdown and absorption of dietary fat in the intestines; they are, however, poorly tolerated by the person who is obese because the effects of fat malabsorption are unpleasant.

These drugs also interfere with the absorption of some necessary vitamins. Fat substitutes such as Olestra, while technically not drugs, attempt to recreate the pleasant taste that fat adds to food, but create the same negative side effects as digestive inhibitors. Unless an obese individual has also made necessary behavioral changes, excess weight returns quickly when appetite suppressants or malabsorptive agents are stopped.

The use of any drug is associated with unwanted side effects, so that the decision to take a drug must come after the potential side effects are weighed against the potential benefits. No drug, current or past, has had such dramatic effects on obesity that it warrants its casual use. While most of the immediate side effects that may occur are reversible, the long-term effects, in many cases, are unknown. Even after a new drug successfully negotiates the stringent FDA approval process, its widespread use over a longer time frame may lead to the side effects that were not initially observable in the test population. Two popular obesity drugs of the early 1990s have already been withdrawn from the market because of unanticipated and severe cardiac problems. Meridia, just released in 1997, is already under scrutiny by a consumer group for its relationship to several deaths. Nevertheless, studies show that when obesity drugs are combined with behavioral changesand especially with a portion controlled dietweight loss is significantly greater than in a control group treated with behavior modification alone, at least after six months. It remains to be proved whether drug-assisted weight loss is long lasting.

Alternative treatment

The Chinese herb, ephedra (Ephedra sinica ), combined with caffeine, exercise, and a low-fat diet, can cause a temporary increase in weight loss, at best. However, ephedra and caffeine are both central nervous system (CNS) stimulants, and the large doses of ephedra required to achieve the weight loss can also cause anxiety, irritability, and insomnia . Further, ephedra has been implicated in more serious conditions, such as seizure and stroke. Ephedra should not be used by anyone with a history of diabetes, heart disease, or thyroid problems.

HEIGHT AND WEIGHT GOALS
Men
Height Small Frame Medium Frame Large Frame
52 128-134 lbs. 131-141 lbs. 138-150 lbs.
53 130-136 133-143 140-153
54 132-138 135-145 142-153
55 134-140 137-148 144-160
56 136-142 139-151 146-164
57 138-145 142-154 149-168
58 140-148 145-157 152-172
59 142-151 148-160 155-176
510 144-154 151-163 158-180
511 146-157 154-166 161-184
60 149-160 157-170 164-188
61 152-164 160-174 168-192
62 155-168 164-178 172-197
63 158-172 167-182 176-202
64 162-176 171-187 181-207
Women
Height Small Frame Medium Frame Large Frame
410 102-111 lbs. 109-121 lbs. 118-131 lbs.
411 103-113 111-123 120-134
50 104-115 113-126 112-137
51 106-118 115-129 125-140
52 108-121 118-132 128-143
53 111-124 121-135 131-147
54 114-127 124-141 137-151
55 117-130 127-141 137-155
56 120-133 130-144 140-159
57 123-136 133-147 143-163
58 126-139 136-150 146-167
59 129-142 139-153 149-170
510 132-145 142-156 152-176
511 135-148 145-159 155-176
60 138-151 148-162 158-179

Diuretic herbs, which increase urine production, can cause short-term weight loss, but cannot help patients achieve lasting weight control. The body responds to heightened urine output by increasing thirst to replace lost fluids, and patients who use diuretics for an extended period of time retain water even in the presence of the diuretic. In moderate doses, psyllium, a mucilaginous herb available in bulk-forming laxatives like Metamucil, absorbs fluid and makes patients feel as if they have eaten enough. Red peppers, mustard, and dandelion are said to generate weight loss by accelerating the metabolic rate. Dandelion also counteracts the desire for sweet foods. Walnuts contain serotonin, the brain chemical that signals satiety.

Acupressure and acupuncture can also suppress food cravings. Visualization and meditation can create and reinforce a positive self-image that enhances determination to lose weight. By improving physical strength, mental concentration and emotional serenity, yoga can provide the same benefits.

The correct balance of the basic food groups is also important, and believed by some experts to enhance the metabolic rate.

Prognosis

As many as 85% of dieters who do not exercise on a regular basis regain their lost weight within two years. In five years, the figure rises to 90%. Repeatedly losing and regaining weight (yo-yo dieting) encourages the body to store fat and may increase a patient's risk of developing heart disease. The primary factor in achieving and maintaining weight loss is a lifelong commitment to regular exercise and sensible eating habits.

Prevention

Obesity experts suggest that a key to preventing excess weight gain is monitoring fat consumption rather than counting calories; in fact, the National Cholesterol Education Program maintains that only 30% of calories should be derived from fat. Only one-third of those calories should come from saturated fats (the kind of fat found in high concentrations in meat, poultry, and dairy products). However, total caloric intake cannot be ignored, since it usually the slow accumulation of excess caloric intake, regardless of its source, that results in obesity. Erring on the side of 25 excess calories a day, a single cookie will result in a five-pound weight gain by the end of a year. Without recognition of the problem, weight balloons up another 45 pounds by the end of 10 years, and the return to normal weight is an arduous process. Because most people eat more than they think they do, keeping a detailed and honest food diary is a useful way to recognize eating habits. Eating three balanced, moderate-portion meals a daywith the main meal at mid-dayis a more effective way to prevent obesity than fasting or crash diets, which convince the body that there is an ongoing famine. After 12 hours without food, the body has depleted its stores of readily available energy, and hunkers down to begin protecting itself for the long term. Metabolic rate starts to slow, and breakdown of muscle tissue for the raw materials needed for energy maintenance begins. Until more food appears, famine mode persists and deepens; when the fast is lifted, the body is in a state of slowed metabolism, has a bit less muscle, and requires less food than before the fast. Exercise increases the metabolic rate by creating muscle, which burns more calories than fat. When regular exercise is combined with consistent, healthful meals, calories continue to burn at an accelerated rate for several hours.

Finally, encouraging healthful habits in children is a key to preventing childhood obesity and the health problems that follow in adulthood.

Resources

BOOKS

Aronne, Louis J. "Obesity and Weight Management." In Textbook of Primary Care Medicine. 3rd ed. Edited by John Noble, M.D. St. Louis, MO: Mosby, 2001.

The Editors of Time-Life Books. The Medical Advisor: The Complete Guide to Alternative & Conventional Treatments. Alexandria, VA: Time Life, Inc. 1996.

Harris, Dan R., ed. Diet and Nutrition Sourcebook. Detroit, MI: Omnigraphics, 1996.

Wilmore, Jack H. and David L. Costill. "Obesity, Diabetes, and Physical Activity." In Physiology of Sport and Health. 2nd ed. Champaign, IL: Human Kinetics, 1999.

PERIODICALS

Jensen, Michael D., ed. "Obesity." Medical Clinics of North America 84, no.2 (March 2000): 305518.

Lustig, Robert H. "The Neuroendocrinology of Obesity." Endocrinology and Metabolism Clinics 30, no. 3 (September 2001): 765785.

Patel, Manesh R. and Darren K. McGuire. "Pounds of Prevention." American Heart Journal 142, no.3 (September 2001): 38890.

Rocchini, Albert P. "Childhood Obesity and A Diabetes Epidemic." New England Journal of Medicine 346, no. 11 (March 14, 2002): 854855.

ORGANIZATIONS

American Dietetic Association. 216 West Jackson Blvd., Chicago, IL 60606-6995. <http://www.eatright.org>.

American Obesity Association. 1250 24th St. NW, Washington D.C. 20037. <http://www.obesity.org>.

Shape Up America. 6707 Democracy Blvd., Suite 306, Bethesda, MD 20817. <http://www.shapeup.org/general/index.html>.

Weight-Control Information Network. 1 Win Way, Bethesda, MD 20892-3665. <http://www.niddk.nih.gov/health/nutrit/win.html>.

Elizabeth Reid, M.D.

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Obesity

Obesity

Definition

Obesity is an abnormal accumulation of body fat, usually 20 percent or more over an individual's ideal body weight. Obesity is associated with increased risk of illness, disability, and death.

The branch of medicine that deals with the study and treatment of obesity is known as bariatrics. As obesity has become a major health problem in the United States, bariatrics has become a separate medical and surgical specialty.

Description

Childhood obesity is in the early 2000s a significant health problem in the United States. Obese children and adolescents are at increased risk for developing diabetes, hypertension , coronary artery disease, sleep apnea, orthopedic problems, and psychosocial disorders.

Obesity involves excessive weight gain and fat accumulation. For children and adolescents, obesity is defined in terms of body mass index (BMI) percentile. BMI is a formula that considers an individual's height and weight to determine body fat and health risk, and it is used differently for children and adolescents than it is for adults. In adults, BMI often misrepresents obesity because it does not consider healthy weight from muscle tissue; therefore, body fat percentage is considered a more accurate method for determining obesity in adults. In children and adolescents, because body fat changes as they mature, BMI is gender- and age-specific and plotted on gender-specific growth charts to determine BMI-forage. Curved lines on the chart (percentiles) are used by healthcare professionals to identify children and adolescents at risk for overweight and obesity. Children and adolescents with a BMI-for-age in the 85th to 95th percentile are considered overweight and at risk for obesity, and those with a BMI-for-age greater than the 95th percentile are considered obese.

Demographics

According to the American Obesity Association and the Centers for Disease Control and Prevention, 30.3 percent of children aged six to 11 years are overweight and 15.3 percent are obese, and 30.4 percent of adolescents aged 12 to 19 years are overweight and 15.5 percent are obese. From 1980 to 2004, the prevalence of obesity among children quadrupled, and the prevalence of obesity in adolescents more than doubled. Overweight and obesity is more prevalent in boys (32.7%) than girls (27.8%). Obesity is more common in African American, Hispanic American, and Native American children and adolescents, than among Caucasians of the same ages.

Causes and symptoms

Although obesity can be a side effect of certain hormonal disorders or use of certain medications, the primary cause of obesity in children and adolescents is excess calorie consumption coupled with a sedentary lifestyle. Children and adolescents living in the twenty-first century are the most inactive generation ever. The majority of schools no longer offer daily physical education classes; and active leisure activities, such as bicycle riding, have been replaced by sedentary activities, such as television watching and playing computer games. Studies have documented dramatic changes in childhood food consumption from the 1970s to 2004. Fast foods and foods eaten at other restaurants have increased by 300 percent since 1977, and soft drink consumption has also increased significantly. In addition, standard meal portion sizes and snacking have increased.

Obesity is the result of a complex interaction of genetics and environmental factors. Genetics influence how the body regulates appetite and metabolism, while certain environmental factors encourage excess calorie consumption. The body requires a certain amount of energy for basic metabolism and to support additional physical activity. When calories consumed from food and beverages equal calories expended during physical activity, body weight is maintained. When calories consumed exceed calories expended, weight gain results. To gain one pound, 3,500 additional calories must be consumed. In American society, excess calories are easily consumed just by drinking soft drinks and eating "supersized" fast food meals. A sedentary lifestyle results in far fewer calories being burned daily.

The major symptoms of obesity are excessive weight gain and the presence of large amounts of fatty tissue. Obesity can cause a number of other conditions, including type 2 diabetes, hypertension, high cholesterol , joint pain , asthma , hypothyroidism , and gallstones. Type 2 diabetes, previously referred to as adult-onset diabetes, has increased dramatically in children, and this increase has been directly linked to obesity.

When to call the doctor

Overweight and obese children should be evaluated by a physician for diabetes, hypertension, high cholesterol, and other medical conditions that are influenced by excessive weight gain. Primary care physicians can be consulted for weight management counseling to help children lose weight.

Diagnosis

Obesity in children and adolescents is diagnosed using the BMI-for-age formula described above, which is used to define obesity. Comorbid conditions, such as diabetes and high cholesterol, are diagnosed using medical laboratory tests.

Treatment

As of 2004, no weight loss drugs were approved for use in children, although some drugs used to treat obesity are approved for use in adolescents age 16 years and older. A few drugs are under investigation for use in children. Although no drugs are specifically approved for pediatric weight loss, some physicians may prescribe them "off-label." Because the side effects of these medications in children are unknown, children should not use adult weight loss drugs.

For extremely obese adolescents, surgical procedurescalled bariatric surgerymay be performed, but only rarely. These procedures involve significant surgical alteration of the digestive tract and require substantial modification of diet after the surgery to much less than 1,000 calories per day. The long-term effects on growth and development from severe postoperative calorie restriction are not unknown, and weight loss surgery should only be performed on adolescents as a last resort.

The most effective treatment for obese children and adolescents is behavior and lifestyle modification under the guidance of a physician or weight management specialist experienced in dealing with children and adolescents. Behavior and lifestyle modification involves the following:

  • assessment of child's and family's eating habits
  • implementation of a regular, safe exercise program and increasing active leisure activities
  • limiting television viewing and other sedentary activities
  • setting reasonable goals and monitoring goal achievement using positive, non-food-related incentives
  • counseling regarding how to keep a food/activity diary to track progress
  • extensive support by involving entire family and/or joining a weight loss group of peers

Alternative treatment

Alternatives for weight loss involve the use of ephedra-containing drugs or herbal preparation or the use of diuretics and laxatives . Both of these practices are unsafe, especially for children and adolescents. Because ephedra can cause severe cardiac side effects, the Food and Drug Administration has issued warnings against its use. Diuretics and laxatives can result in severe dehydration and improper absorption of nutrients.

Acupressure and acupuncture can suppress food cravings. Visualization and meditation can create and reinforce a positive self-image that enhances the patient's determination to lose weight. By improving physical strength, mental concentration, and emotional serenity, yoga can provide the same benefits.

Given the drastic increase in childhood obesity, special summer programs and therapeutic schools have been formed to help children lose weight. Summer camp programs that focus on healthy eating and exercise habits are available for overweight and obese children. In addition, in early 2004, the first alternative school for overweight and obese children, which operates like other private and charter schools, but with a focus on healthy weight loss and maintenance, was established.

Prognosis

Obese and overweight children and adolescents are more likely to be obese or overweight as adults. According to the American Obesity Association, obese children aged 10 to 13 have a 70 percent chance of remaining obese for the rest of their lives. Obese individuals are at increased risk for many other diseases and early death. Behavior and lifestyle modification programs involving positive goal-setting, increased exercise, and group support can help children and adolescents successfully and safely lose weight.

Prevention

Obesity can be prevented by instilling healthy eating and regular exercise habits in children at an early age. Minimizing and structuring daily time for sedentary activities like television viewing and encouraging outdoor activities such as bicycle riding, walking, running, and active play , and active indoor activities such as dancing can help increase physical activity. Dietary modifications to help prevent obesity include limiting soft drink and fast food consumption, monitoring food portion sizes, and providing a well-balanced diet.

Nutritional concerns

Nutrition is a primary factor for weight management of obese children and adolescents. Poor nutrition and dietary habits can lead to weight gain and obesity. Dietary modification is important for helping children lose weight and prevent obesity.

KEY TERMS

Adipose tissue Fat tissue.

Bariatrics The branch of medicine that deals with the prevention and treatment of obesity and related disorders.

Ghrelin A peptide hormone secreted by cells in the lining of the stomach. Ghrelin is important in appetite regulation and maintaining the body's energy balance.

Hyperlipidemia A condition characterized by abnormally high levels of lipids in blood plasma.

Hyperplastic obesity Excessive weight gain in childhood, characterized by an increase in the number of new fat cells.

Hypertension Abnormally high arterial blood pressure, which if left untreated can lead to heart disease and stroke.

Hypertrophic obesity Excessive weight gain in adulthood, characterized by expansion of already existing fat cells.

Ideal weight Weight corresponding to the lowest death rate for individuals of a specific height, gender, and age.

Leptin A protein hormone that affects feeding behavior and hunger in humans. As of 2004 it is thought that obesity in humans may result in part from insensitivity to leptin.

The following nutritional guidelines can help in the management of obesity:

  • Limit soft drink consumption to one per day or less. One 12-ounce can of soda has 120 calories or more. Often, children and adolescents consume "super-size" sodas that may contain up to 1,000 calories.
  • Limit fast food restaurant visits to one per week, and choose healthy options like grilled chicken and smaller sized portions of high-calorie items.
  • Monitor food serving sizes.
  • Increase consumption of fruits, vegetables, high-fiber foods, and whole-grain foods.
  • Be aware that "low-fat" foods often substitute sugar for fat, and calories may actually be the same as the regular or high-fat version.

Parental concerns

Parents of obese children and adolescents should be concerned for their current and future health, since obesity can result in diabetes, hypertension, and coronary artery disease. Losing weight can be very difficult for obese children, and parental support is essential for success. Because children model behavior after their parents, obesity often affects both parents and children. Parents should strive to have healthy eating habits and exercise regularly to be effective role models for their children. Making healthy eating and exercise a family priority is better for everyone and helps reinforce positive changes in behavior for the obese child.

Obese children and adolescents are more susceptible to eating disorders, negative self-esteem and body image, and depression due to peer influences. Counseling, peer group therapy, and family therapy may be required to support lifestyle modifications for obese children and adolescents.

Resources

BOOKS

Burniat, Walter, et al. Child and Adolescent Obesity: Causes and Consequences, Prevention and Management. Cambridge, UK: Cambridge University Press, 2002.

Kiess, Wieland, et al. Obesity in Childhood and Adolescence. Basel, Switzerland: S. Karger AG, 2004.

PERIODICALS

Eissa, M. A. H., and K. B. Gunner. "Evaluation and Management of Obesity in Children and Adolescents." Journal of Pediatric Health Care 18(March 2004): 3538.

Manson J. E., et al. "The Escalating Pandemics of Obesity and Sedentary Lifestyle." Archives of Internal Medicine 164(February 9, 2004): 249258.

McWhorter, J. W., et al. "The Obese Child: Motivation as a Tool for Exercise." Journal of Pediatric Health Care 17(February 2003): 1117.

Ritter, J. "Obese Teens Turn to Surgery of Last Resort." Chicago Sun-Times, March 29, 2004.

St-Onge M. P., et al. "Changes in Childhood Food Consumption Patterns: A Cause for Concern in Light of Increasing Body Weights." American Journal of Clinical Nutrition 78(December 2003): 106873.

ORGANIZATIONS

American Dietetic Association. Web site: <www.eatright.org>.

American Obesity Association (AOA). 1250 24th Street NW, Suite 300, Washington, DC 20037. Web site: <www.obesity.org>.

American Society of Bariatric Physicians. 5453 East Evans Place, Denver, CO 802225234. Web site: <www.asbp.org>.

American Society for Bariatric Surgery. 7328 West University Avenue, Suite F, Gainesville, FL 32607. Web site: <www.asbs.org>.

National Institute of Diabetes and Digestive and Kidney Diseases. 31 Center Drive, USC2560, Building 31, Room 9A-04, Bethesda, MD 208922560. Web site: <www.niddk.nih/gov>.

Shape Up America! Web site: <www.shapeup.org/>.

WEB SITES

"BMI for Children and Teens." Centers for Disease Control and Prevention, 2004. Available online at <www.cdc.gov/nccdphp/dnpa/bmi/bmi-for-age.htm> (accessed October 26, 2004).

"Fitness for Your Child." IDEA Health and Fitness Association. Available online at <www.ideafit.com/articles/fitness_child.asp> (accessed October 26, 2004).

"Obesity in Youth." American Obesity Association. Available online at <www.obesity.org/subs/fastfacts/obesity_youth.shtml> (accessed October 26, 2004)

OTHER

Childhood Assessment Calculator. Available online at <www.shapeup.org/oap/entry.php> (accessed October 26, 2004).

Jennifer E. Sisk, MA

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Sisk, Jennifer. "Obesity." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

Sisk, Jennifer. "Obesity." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1G2-3447200410.html

Sisk, Jennifer. "Obesity." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3447200410.html

Obesity

Obesity

PREVALENCE OF OBESITY

CONSEQUENCES OF OBESITY

ENVIRONMENTAL EXPLANATIONS

EARLY PSYCHOLOGICAL THEORIES

DIETARY RESTRAINT

BIOLOGICAL EXPLANATIONS

BIBLIOGRAPHY

Obesity results from chronic energy intake that exceeds energy expenditure and is characterized by excessive body fat. The precise assessment of an individuals body fat is an expensive and complicated procedure. Instead, body mass index (BMI), though somewhat controversial, is used commonly because it is easy to assess and correlates highly with body fat. BMI is calculated by taking an individuals weight in kilograms and dividing it by that individuals height in meters squared (kg/m2). For adults a healthy BMI is between 18.5 and 24.9. A BMI of 25 to 29 is classified as overweight, obesity is defined as a BMI of 30 to 39, and clinically severe obesity is defined as a BMI of 40 or more. Because of the pervasive social stigma associated with the term obesity, it is avoided for children; at risk for overweight and overweight are the recommended terms. To account for normal age and sex differences in childrens body fat, at risk for overweight is defined as a BMI at or above the 85th percentile and overweight as a BMI at or above the 95th percentile of the sex-specific BMI-for-age growth charts.

PREVALENCE OF OBESITY

Health statistics for the United States reveal a dramatic upsurge in obesity prevalence during the early 1980s, and the rates have continued to rise. U.S. national health statistics in 2007 estimated that 34.1 percent of adults were overweight, 32.2 percent obese, and 4.8 percent clinically obese; 17.1 percent of children and adolescents age six to nineteen were estimated to be overweight, and 16.5 percent were at risk for overweight. Sociodemographic risk factors for obesity include being of a racial/ethnic minority and being of low socioeconomic status.

CONSEQUENCES OF OBESITY

Obesity is associated with high morbidity and mortality rates. The medical sequelae of obesity include type II diabetes, coronary heart disease, stroke, osteoarthritis, sleep apnea, and some cancers, including breast and colon cancer.

Among the most insidious and common adverse effects are the socioemotional consequences of obesity. Obese individuals are significantly more likely to experience social stigmatization and discrimination in all domains, including education, employment, social relationships, and health care. Also, obesity is associated with low self-esteem, body image disorders, anxiety, and depression. Associations between BMI and body satisfaction vary with race/ethnicity and gender. African Americans have a higher mean BMI than do European Americans but tend also to have greater body satisfaction. Generally, females report significantly lower body satisfaction than do males regardless of race/ethnicity.

ENVIRONMENTAL EXPLANATIONS

The escalating rates of obesity since the 1980s are attributable to a complex interaction of environmental, sociocultural, behavioral, and biological/genetic factors that is not well understood. At a macrosystemic level, U.S. food policy is fundamentally at odds with the goal of healthful eating. Food is overproduced, and as a result of the abundant supply, food companies must compete aggressively for market share. Cheap, palatable, and accessible energydense foods are mass-marketed and offered in portions vastly disproportionate to individuals caloric needs. A marked shift toward away-from-home and prepared food consumption probably has resulted from time constraints caused by a rise in dual-career and single-parent working families. In 1977, 9.6 percent of meals were eaten at restaurants and fast food outlets; by 1996 that proportion had risen to 23.5 percent.

Over roughly the same period consumption of highfructose corn syrup (HFCS) increased 1000 percent or more. HFCS is used instead of sugar (glucose) as a caloric sweetener in many foods and all soft drinks; however, it is digested, absorbed, and metabolized differently than glucose is. Fructose, unlike glucose, distorts levels of insulin, leptin, and ghrelin, the hormones that act as key signals in food regulatory processes and body weight, making dietary fructose a prime suspect in the obesity epidemic.

A sedentary lifestyle is an important contributing factor, especially in light of the fact that decreased energy expenditure has been accompanied by increased energy consumption. A sedentary lifestyle is a natural consequence of a built environment characterized by urban sprawl that necessitates travel by car or mass transit and time-consuming commutes. Technological advancement that reduces energy output, low-energy office occupations, and leisure preferences such as television viewing and computer use increase the probability of a physically inactive lifestyle.

EARLY PSYCHOLOGICAL THEORIES

Two classic psychological theories of obesity predate the onset of the obesity epidemic. To explain differences in the eating patterns of obese and normal-weight individuals, in 1968 Stanley Schacter proposed the internal-external theory of obesity and in 1972 Richard Nesbitt proposed the set point theory. Schacter hypothesized that obese individuals are more likely to be responsive to cues from the external environment such as the sight and palatability of food, whereas normal-weight individuals are more likely to eat in response to internal physiological cues. Nesbitt countered with the hypothesis that each individual has a unique, biologically determined ideal weight, with obese individuals having an above-average set point. He theorized further that societal ideals of thinness cause obese individuals to restrain their intake and eat below their set points, essentially causing a chronic state of deprivation and hyperresponsiveness to external food cues. These models of obesity have faded in importance because of a lack of empirical support. However, the derivative construct of dietary restraint and its effect on individuals eating patterns continues to generate much research and some controversy.

DIETARY RESTRAINT

Dietary restraint is defined as the deliberate and persistent restriction of food to promote weight loss. Restraint theory proposes that restrained eaters may develop disordered eating patterns as a result of the stress inherent in chronic appetitive self-control. Although research has supported a relationship between dietary restraint and disinhibited eating, the validity of the restraint measurement scales is at issue and further work on more definitive construct measurement and the role of dietary restraint in disordered eating is warranted.

BIOLOGICAL EXPLANATIONS

Obesity also is explained by reference to biological processes. Research indicates that neuroendocrinological processes, most centrally the hypothalamic-pituitary-adrenal (HPA) axis, figure prominently in obesity. The HPA axis, which consists of the hypothalamus and the pituitary and adrenal glands, is a key player in stress regulation as well as in physiological processes such as digestion, energy use, and mood. Stress, which is inherent in the daily demands of the twenty-first-century environment, causes elevated cortisol secretion by the HPA axis. Protracted stimulation of the HPA axis results in a flood of neuroendocrine-endocrine disturbances that in turn cause insulin resistance and visceral (abdominal) obesity. Visceral obesity carries the highest risk for comorbidities.

Genetic research is still in its early stages. There is substantial heritability of individual differences in BMI. However, more than twenty genes, hypothesized as working in conjunction with a wide range of environmental factors, have been linked to obesity: Clearly, obesity is causally very complex. Equally clearly, however, obesity is an urgent health problem that will continue to be a challenge for the foreseeable future.

SEE ALSO Body Image; Body Mass Index; Disease; Overeating

BIBLIOGRAPHY

Bjorntorp, Per, and Roland Rosmond. 2000. Neuroendocrine Abnormalities in Visceral Obesity. International Journal of Obesity and Related Metabolic Disorders 24 (Supplement 2): S80S85.

Bray, George A., Samara Joy Nielsen, and Barry M. Popkin. 2004. Consumption of High-Fructose Corn Syrup in Beverages May Play a Role in Obesity. American Journal of Clinical Nutrition 79: 537543.

Centers for Disease Control and Prevention. National Center for Health Statistics. 2006. National Health and Nutrition Examination Survey Data. Hyattsville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. http://www.cdc.gov/nchs.htm.

Nesbitt, Richard E. 1972. Hunger, Obesity, and the Ventromedial Hypothalamus. Psychological Review 79 (6): 433453.

Ogden, Cynthia L., Margaret D. Carroll, Lester R. Curtin, et al. 2006. Prevalence of Overweight and Obesity in the United States, 19992004. Journal of the American Medical Association 295 (13): 15491555.

Ruderman, Audrey J. 1986. Dietary Restraint: A Theoretical and Empirical Review. Psychological Bulletin 99: 247262.

Schacter, Stanley. 1968. Obesity and Eating. Science 161: 751756.

Smith, D. E., J. K. Thompson, J. M. Raczynski, and J. E. Hilner. 1999. Body Image among Men and Women in a Biracial Cohort: The CARDIA Study. International Journal of Eating Disorders 25 (1): 7182.

Stice, Eric, Melissa Fisher, and Michael Lowe. 2004. Are Dietary Restraint Scales Valid Measures of Acute Dietary Restriction? Unobtrusive Observational Data Suggest Not. Psychological Assessment 16 (1): 5159.

Joan K. Orrell-Valente

Kim Jones

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Obesity

Obesity

Obesity , defined as a body mass index of 30 or greater, is an epidemic in the United States and other industrialized nations, and it is rapidly becoming one in developing nations. As countries transition to westernized lifestyles, obesity tends to increase. Obesity rates vary from as little as 2 percent in some Asian countries to as much as 75 percent in some Pacific nations. There are more than 300 million obese persons in the world, and more than 750 million overweight persons. In the United States, 34 percent of adults are over-weight and 30.5 percent are obese. Between 1980 and 2000, the percentage of overweight children ages six to eleven doubled, from 7 percent to 15 percent, and the percentage of overweight adolescents ages twelve to nineteen tripled, from 5 percent to 16 percent (Ogden, et al.). In Europe, the thinnest country is Sweden, with about 10 percent obesity, while the fattest is Lithuania, with about 79 percent obesity. The sad fact is the prevalence of obesity appears to be increasing in all countries.

An obese person has a 50 to 100 percent increased risk of premature death compared to someone of normal weight. In the United States, more than 300,000 deaths a year are attributable to obesity. Obesity is associated with type 2 diabetes , coronary heart disease , stroke , hypertension , elevated blood cholesterol , some cancers (e.g., colon, endometrial, kidney, gallbladder, and postmenopausal breast cancer ), osteoarthritis , gallbladder disease, and respiratory disease. In addition, obesity is often associated with discrimination and prejudice, causing some obese people to suffer poor self-esteem and reduced quality of life. The health care costs attributable to obesity exceed $100 billion a year in the United States, more than 6 percent of the total health care costs.

What Causes Obesity?

Obesity is caused by many factors. A person's weight is determined by a combination of genes , metabolism , behavior, culture, and environment . Genes and metabolism may help explain about 25 to 40 percent of body weight. However, a person's environment overwhelms the minor influences of biology. While genes may increase one's risk for obesity, they do not by themselves cause obesity. Genes certainly can't explain the rapidly increasing prevalence of obesity around the world.

For most people, obesity results from eating too much and not being active enough. The overwhelming factors responsible for obesity are environmental. Modern Western society encourages poor diets and lack of exercise. For example, portion sizes continue to increase. Americans were eating about 200 more calories per day in 2003 than they were in 1993. Fast-food restaurants encourage customers to "super size" and purchase "value" meals. Many target children, using well-known movie stars and cartoon characters in their advertising. Further, people eat out more often than in the past and many restaurants offer huge portion sizes. Americans seem determined to get as much food as they can for their money.

Television contributes to obesity through commercials urging people to buy food of low nutritional value, and by encouraging sedentary behavior. Many people tend to snack while watching television. Americans simply don't get enough physical activity. Less than one-third of American adults report that they do at least thirty minutes of brisk walking or other moderate activity on most days of the week, and almost half do no leisure-time activity at all. Almost half of U.S. high school students watch television more than two hours every day. This lack of physical activity is contributing to the increases in obesity and to other health-related conditions.

Treatment of Obesity

Weight loss in obese persons improves health. Weight losses of ten to twenty pounds have been shown to lower blood pressure , blood cholesterol, and blood glucose (in persons with type 2 diabetes), and to improve other health problems. An obese person does not have to lose fifty or a hundred pounds to realize health benefits, however, for even modest losses of weight can lead to major health benefits.

The Cost of Obesity

American spend more than $33 billion annually on weight loss, including low-calorie foods and fees at weight-loss clinics. A study estimated the health care cost of overweight and obesity to be $120 billion. This includes direct costs, such as doctor visits and medication, and indirect costs, such as wages lost by people too ill to work and the value of future earnings cut short by premature death. There are 63 million doctor visits per year related to obesity, and approximately 40 million workdays are lost.

Paula Kepos

Diets

Reducing calories is one requirement for weight loss. Cutting only 100 extra calories a day from one's diet will lead to a weight loss of 10 pounds in a year, while cutting 500 calories a day will lead to a loss of 50 pounds in a year. Most health organizations recommend a specific distribution of calories. For example, about 25 to 30 percent of total calories should be from fat (mainly unsaturated fat, such as olive oil, corn oil, and safflower oil), 15 percent from protein , and 50 to 60 percent from carbohydrates (mainly complex carbohydrates, such as fruits and vegetables). Recommended total calories should be based on height, weight, age, and activity level. A plant-based diet, consisting of an abundance of fresh vegetables and fruit and limited in calories, seems to be a healthful one for most people.

Physical Activity

Burning only an extra 100 calories a day by walking briskly for about 20 minutes will lead to a weight loss of about 10 pounds a year, while burning an extra 300 calories by walking briskly for about 60 minutes a day will lead to a weight loss of about 30 pounds. Physical activity contributes to weight loss, decreases abdominal fat, increases cardiorespiratory fitness, and helps with maintenance of lost weight. Any aerobic exercise, such as swimming, bicycling, jogging, skiing, or dancing, leads to these benefits, but for most obese people brisk walking seems to be the easiest activity to do. Other forms of exercise, such as resistance training or lifting weights, can also be helpful in a weight loss program. Finding ways to be more active every day, such as walking up a flight of stairs rather than taking the elevator, or walking somewhere rather than driving, can help a person burn calories without much effort.

Combined Diet and Exercise

The combination of a reduced-calorie diet and increased physical activity will lead to better weight loss than either one done separately. Small changes in diet and physical activity done each day is the key to long-term, successful weight loss for most obese people.

see also Body Image; Body Mass Index; Childhood Obesity; Fad Diets; Fast Foods; Overweight; Weight Loss Diets; Weight Management.

John P. Foreyt

Bibliography

Flegal, Katherine M.; Carroll, Margaret D.; Ogden, Cynthia L.; and Johnson, Clifford L. (2002). "Prevalence and Trends in Obesity among U.S. Adults, 19992000." Journal of the American Medical Association 288(14):17231727.

Foreyt, John P.; McInnis, Kyle J.; Poston, Walker S. C.; and Rippe, James M.; eds. (2003). Lifestyle Obesity Management. Malden, MA: Blackwell.

Ogden, Cynthia L.; Flegal, Katherine M.; Carroll, Margaret D.; and Johnson, Clifford L. (2002). "Prevalence and Trends in Overweight among U.S. Children and Ado lescents, 19992000." Journal of the American Medical Association 288(14):17281732.

Poston, Walker S. C., and Foreyt, John P. (1999). "Obesity Is an Environmental Issue." Atherosclerosis 146:201209.

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Obesity

Obesity

A condition of having an excessive accumulation of fat in the body, resulting in a body weight that is at least 20 percent above normal when measured against standard tables of optimal weight ranges according to age, sex, height, and body type.

Individuals who are 20 percent overweight are considered slightly obese. Those who are 40 percent above standard weight are moderately obese, while those 50 percent above it are morbidly obese. Persons who exceed desired weight levels by 100 pounds (45 kg) or more are hyperobese. Obesity is a serious health problem in the United States. Studies suggests that between 10 and 20 percent of Americans are slightly to moderately obese. Obesity places stress on the body's organs, and is associated with joint problems, high blood pressure, indigestion, dizzy spells, rashes, menstrual disorders, and premature aging . Generally, when compared to persons of normal weight, obese individuals suffer more severely from many diseases, including degenerative diseases of the heart and arteries, and a shorter life expectancy. Obesity can also cause complications during childbirth and surgery.

Obesity may be familial, as the body weight of children appears to be linked to that of their parents. Children of obese parents have been found to be 13 times more likely than other children to be obese, suggesting a genetic predisposition to body fat accumulation. Recent animal research suggests the existence of a "fat gene," and the tendency toward a body type with an unusually high number of fat cellstermed endomorphic appears to be inherited. However, the generational transmission of obesity may be as cultural as it is genetic, as early feeding patterns may produce unhealthy eating habits.

Some cases of obesity have a purely physiological cause, such as glandular malfunction or a disorder of the hypothalamus . Individuals with a low production of the hormone thyroxin tend to metabolize food slowly, which results in excess unburned calories. When more calories are consumed than the body can metabolize, excess calories are stored in the body as fat, or adipose tissue. Some persons with hypoglycemia have a specific metabolic problem with carbohydrates that can also lead to the storage of unburned calories as fat.

In the great majority of cases, however, obesity is caused by overeating. Overeating itself often combines physical and psychological components. People may eat compulsively to overcome fear or social maladjustment, express defiance, or avoid intimate relationships. However, researchers have also suggested physical correlates for overeating, including deficits in the neurotransmitter serotonin that increase cravings for carbohydrates, and possibly a higher "set point" for body weight that makes obese persons feel hungry more often than thinner people. This raised set point could result from both genetics and early nutritional habits. Lack of exercise and sedentary living also contribute to obesity.

The most effective treatment of obesity includes both the reduction of surplus body fat and the elimination of causative factors, and is best accomplished under medical supervision. An appropriate weight loss plan includes exercise (which burns calories without slowing metabolism), reduced food intake, behavior modification to change food-related attitudes and behavior, and psychotherapy if there are underlying psychological causes for overeating. Other possible treatment measures include hormone therapy, appetite-suppressant drugs, and surgical intervention to alter satiety signals by reducing the size of the stomach and intestines.

Behavior modification has been especially successful and widely used in the treatment of obesity. Treatment techniques include stimulus control (removing environmental cues that play a role in inappropriate eating), eating management (slowing the pace of eating to allow satiation to catch up with it), contingency management (applying a system of positive reinforcement and punishments), and self-monitoring of daily dietary intake and factors associated with it. Despite all of the available treatments, the difficulty of reversing obesity in adults makes

OBESITY IN ADOLESCENT YOUTHS (AGES 6 TO 17) IN THE UNITED STATES

Prevalence of overweight Doubled since 1965
Number who are overweight 4.7 million
Percent who are overweight 11 percent
Related disorders Elevated blood cholesterol; high blood pressure; increased adult mortality
Social consequences Excluded from peer groups, discriminated against by adults, experience psychological stress, poor body image, and low self-esteem.

preventative treatment an important factor during childhood . Today, an increasing percentage of children in the United States are overweight. Recent studies have shown that metabolic rates of children are lower when they watch television than when they are at rest. Unhealthy eating patterns and behaviors associated with obesity can be addressed by programs in nutrition, exercise, and stress management involving both children and families.

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obesity

obesity is most commonly defined as a condition of weighing at least 20% over ideal body weight, where ideal body weight is determined in the US by the 1959 or 1983 Metropolitan Life Insurance Company Tables. Like many aspects of obesity, use of life insurance tables as the sole indicator remains controversial. These insurance charts do not take into account the changes in ideal weight with age or provide information on body fat distribution; nor do they base measurements on all ethnic groups and those of the lower socioeconomic classes. To counter such biases, obesity can be determined by body mass index (which relates weight to height) and the percentage of body fat.

The causes of obesity continue to be debated and studied. Though it has long been considered the simple result of too little exercise and too much eating, new research suggests there may also be some hereditary influence, and particularly that the genetic tendency for obesity may be correlated to the mother's weight. Relatively unusual causes include adult-onset diabetes, deficient thyroid hormone secretion, and, very rarely, tumours of the adrenal gland, pancreas, or pituitary gland. Unexplained abnormal function of the brain's appetite control centre may also play a role. Researchers are particularly concerned about the increasing number of children and adolescents who are overweight in the US and Europe.

Obesity may cause a variety of health complications. Most clearly, overweight has an adverse effect on life expectancy. In general, the greater the degree of overweight, the higher the mortality or excess death rate. Obesity may be associated with elevated blood cholesterol, and has been linked to hypertension, diabetes, cancer, coronary artery heart disease, degenerative arthritis, gall stones, sleep disorders, and depression.

For many the ‘psychological burden’ of being obese in Western cultures, which prize slenderness, particularly in women, is an additional adverse effect. Prior to the nineteenth century, overweight and fatness stood as a sign of health and prosperity, and conveyed social esteem. By the mid and late nineteenth century, a new ethos emerged which championed slenderness as a sign of both beauty and physical health. By the early twentieth century, on the other hand, obesity became associated with laziness, gluttony, and the lower classes. As Keith Walden has written, ‘females who stayed slim demonstrated that they had the money and sense to buy nutritious foods and eat balanced meals, and that they had the time to exercise. They did not have menial jobs which required substantial brawn to perform.’ In twenty-first-century Western culture, especially for whites, and the middle and upper classes, the abhorrence of fat and obesity continues. As Anne Beller describes it, fat is suicidal: a sin at best and at worst a sort of felony. Yet for many African Americans and Hispanics, as well as other ethnic groups, a larger body still holds positive social value.

Suggested treatments for obesity range from a plethora of rarely successful fad diets to medical procedures such as stapling the stomach to reduce intake or shortening the intestines to curtail absorption. The most tried and true method remains adjustment of the energy balance — decreasing caloric intake while increasing energy usage. Vigorous exercise not only ‘burns’ nutrient stores but is also shown in some situations to increase metabolic rate for up to 15 hours after activity. Those with a hereditary tendency toward obesity find it more difficult to lose weight, due to a lower resting metabolic rate and possible complications in appetite regulation. In this regard, and in evolutionary terms, a tendency toward obesity can actually have survival value — a lower metabolic rate and a substantial fat store would allow one to live longer in times of famine. But in the contemporary West, where food is relatively plentiful and slenderness highly prized, it works to one's disadvantage.

Margaret A. Lowe

Bibliography

Beller, A. S. Fat and thin: a natural history of obesity. Farrar, Straus and Giroux, New York.
Walden, K. (1985). The road to Fat City: an interpretation of the development of weight consciousness in Western society. Historical reflections, 12, 331–73.


See also body composition; dieting; energy balance; weight.

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obesity

obesity, condition resulting from excessive storage of fat in the body. Obesity has been defined as a weight more than 20% above what is considered normal according to standard age, height, and weight tables, or by a complex formula known as the body mass index (BMI). It has been estimated that 30% to 35% of Americans are overweight or obese.

Health and Social Implications

Obesity is a major public health concern because it predisposes the individual to many disorders, such as noninsulin-dependent diabetes, hypertension, stroke, and coronary artery disease, and has been associated with an increased incidence of certain cancers, notably cancers of the colon, rectum, prostate, breast, uterus, and cervix. In contemporary American society, obesity also carries with it a sometimes devastating social stigma. Obese people are often ostracized, and discrimination against them, especially in hiring and promotion, is common.

Causes of Obesity

Obesity research has yielded a complicated picture of the underlying causes of the condition. The simple cause is ingestion of more calories than are required for energy, the excess being stored in the body as fat. Inactivity and insufficient exercise can be contributing factors; the less active the person, the fewer calories are needed to maintain normal body weight. Overeating may result from unhealthful patterns of eating established by the family and cultural environment, perhaps exacerbated by psychological distress, an emotional dependence on food, or the omnipresence of high-calorie foods.

In some cases, obesity can come from an eating disorder. It has been shown, for example, that binging for some people releases natural opiates in the brain, providing a sense of well-being and physical pleasure. Other studies have found a strong relationship between obesity in women and childhood sexual abuse.

Some weight-loss experts see obesity as based upon genetics and physiology rather than as a behavioral or psychological problem. For example, rat studies have shown that fat cells secrete a hormone that helps the rat's brain assess the amount of body fat present. The brain tries to keep the amount of that hormone (which also appears to act on the brain area that regulates appetite and metabolic rate) at a set level, resulting in the so-called set point—a weight that the body comes back to, even after resolute dieting. The gene that encodes this hormone, called the obese or ob gene, has been isolated in both rats and humans. In addition, a gene that influences obesity and the onset of diabetes has been identified. It has been estimated that from 8 to 30 different genes may influence obesity.

Treatment

Radical treatments for weight loss have included wiring shut the jaw, operations that reduce the size of the stomach, and intestinal bypass operations circumventing a large area of the small intestine, limiting the area where food is absorbed. The "diet pills" of the 1960s, essentially amphetamines such as Dexedrine, are now seldom prescribed for weight loss. Fenfluramine and dexfenfluramine, drugs formerly used to achieve short-term weight loss, were withdrawn from the market following concerns that they could cause heart valve damage. Drugs to treat obesity now include orlistat (Xenical), which acts to block absorption of dietary fat in the intestine. In 2007 an over-the-counter version of orlistat was approved by the Food and Drug Administration.

Although the study of obesity is yielding many possibilities for treatment, the main focus remains diet (especially a diet limiting fat calories) and exercise, often coupled with emotional and behavioral support. The long-term weight-loss success of most attempts at dieting, however, is notoriously low. Groups such as Overeaters Anonymous, modeled after Alcoholics Anonymous, give support to people with weight problems and eating disorders.

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Obesity

OBESITY

OBESITY is defined as having a body mass index (BMI), which is the relationship of mass to height, of 30 or more, or a weight of about 30 pounds over the maximum desirable for the individual's height. Those at least 100 pounds over their ideal weight are regarded as morbidly obese.

Obesity as a health problem was first discussed by Thomas Short (1690?–1772) in A Discourse Concerning the Causes and Effects of Corpulency. Together with A Method for Its Prevention and Cure (London, 1727). In 1829, the English physician William Wadd (1776–1829) published his Comments on Corpulency, Lineaments of Leanness, Mems on Diet and Dietetics. In 1863, Dr. William Banting (1779–1878) proposed his special "Banting diet" as a treatment for obesity. So-called Bantingism, a diet low in sugar and oily foods, swept across England, making it the first fad diet craze of national proportions. Largely compilations of unscientific speculations and opinions, these early works were supplanted by more systematic studies coming primarily from Germany and France throughout the latter half of the nineteenth century.

The United States did not come into the forefront of obesity research until Hugo Rony's Obesity and Leanness (1940). By the 1950s, the National Institutes of Health served as a catalyst for new investigations into the causes and nature of obesity, launching a new era in evaluating this potentially life-threatening condition. Researchers in the early twenty-first century understand obesity as a complex condition that can be approached from one of four different perspectives: behavioral/psychological aspects; physiological factors; cellular bases in the functions of fat cells; and genetic and molecular factors.

This last aspect came to scientists attention in the late twentieth century. In 1992, a specific gene responsible for obesity in mice was discovered and two others were identified shortly thereafter. Since this pathbreaking work, a number of genes thought to be responsible for predisposing humans to obesity have been uncovered. With the advent of new genetically targeted pharmaceuticals, the prospect of developing a "magic bullet" for people in this category might be on the horizon.

Still, the principal cause of obesity for most Americans is a combination of overeating and sedentary lifestyle. The Centers for Disease Control and Prevention (CDC) has kept data on obesity since 1985 through its Behavioral Risk Factor Surveillance System (BRFSS). The BRFSS reveals an alarming rise in overweight Americans. In 1985, no state had an obese population of 20 percent or more; in 1997, three states reported in that category; by 2000, a staggering 22 states had an obese population of 20 percent or greater. Of even more concern was the rising obesity rate among American children. The CDC reported skyrocketing obesity rates among children ages 12 to 17, from about 4 percent in 1963 to 11 percent by 1994.

As of 2000, 19.8 percent of the total U.S. population was obese. The prevalence of Americans (estimated as high as 47 million) with a metabolic syndrome (high blood pressure, high cholesterol, and high blood sugar and triglycerides) associated with obesity underscored a national need for stricter dietary regimens and more consistent exercise.

BIBLIOGRAPHY

Bray, George A., Claude Bouchard, and W. P. T. James, eds. Handbook of Obesity. New York: Marcel Dekker, 1998.

Centers for Disease Control and Prevention. "Health Topic: Obesity/Overweight." Updated 30 May 2002. Available from http://www.cdc.gov/health/obesity.htm.

Pool, Robert. Fat: Fighting the Obesity Epidemic. New York: Oxford University Press, 2001.

Michael A.Flannery

See alsoHealth Food Industry .

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Obesity

OBESITY

DEFINITION


Obesity is an abnormal accumulation of body fat, usually 20 percent or more over an individual's ideal body weight. Obesity is associated with an increased risk of illness, disability, and death.

DESCRIPTION


Medical researchers have developed charts showing a person's ideal body weight. Ideal body weight means the weight a person should be in order to maintain good health. Ideal body weight depends primarily on three factors: gender, age, and height.

A person is said to be obese if his or her body weight is at least 20 percent more than his or her ideal weight. A range of 20 percent to 40 percent overweight is regarded as mild obesity; 40 percent to 100 percent overweight is regarded as moderate obesity; and more than 100 percent overweight is regarded as severe obesity. Severe obesity is also called morbid obesity. The term "morbid" is used for conditions that can lead to death. A person more than 100 percent overweight is regarded to have such serious health problems that his or her life is threatened.

Obesity: Words to Know

Appetite suppressant:
Drugs that decrease feelings of hunger and control appetite.
Ideal weight:
Weight corresponding to the appropriate, healthy rate for individuals of a specific height, gender, and age.

Obesity can result in many serious, and potentially deadly, health problems. These problems include hypertension (high blood pressure; see hypertension entry), Type II diabetes mellitus (see diabetes mellitus entry), coronary (heart) disease, infertility, and a higher risk for certain forms of cancer (see cancer entry), such as those that affect the colon, prostate, endometrium, and possibly breasts.

According to some estimates, about one-quarter of the U.S. population can be considered obese. Four million of these people may be classified as morbidly obese. About three hundred thousand deaths each year can be blamed on obesity. Public-health leaders point out that obesity is the second leading cause of preventable deaths (after smoking) in the United States.

CAUSES


Part of the food we eat is "burned" to make energy. We use this energy to move, breathe, and carry out all our normal daily activities. The amount of energy present in food is measured in calories. If a person takes in more calories than his or her body burns up, the extra calories are stored in the form of fat.

There are other reasons why an individual's body might retain fat. Some people have a larger appetite than others. Their bodies seem to expect them to eat more often. For others, their bodies do not efficiently convert food to energy. They are more likely to convert the food they eat to fat.

Scientists now think that heredity is an important factor in obesity. That is, some people may inherit from their parents a genetic predisposition to gain weight. A genetic predisposition is a natural tendency over which a person has some, but not complete, control.

This theory has been supported by studies of adopted children. These children tend to have weight patterns more like those of their natural parents than those of their adoptive parents. This finding suggests that the children inherited from their natural parents the tendency to eat normally or excessively.

Even if people do inherit a tendency toward obesity, they do not necessarily have to become overweight. First, they can choose a diet that will reduce the risk of gaining weight. Some types of food, such as carbohydrates, are turned into energy more quickly than other types of foods, such as fats. A beneficial diet high in carbohydrates would consist of cereals, breads, fruits, and vegetables.

Second, a person can choose a lifestyle that will help burn up excess calories. A quiet lifestyle spent watching television will not burn up many calories compared with one that includes jogging, swimming, walking, or other forms of exercise.

Obesity can be caused by other factors as well. For example, a person may feel depressed (see depressive disorders entry) or have a low self-image. In response to those feelings, the person may eat more than his or her body really needs. The excess calories are converted to body fat.

The stage at which a person first becomes obese can affect his or her ability to lose weight. In childhood, excess calories are converted into new fat cells. Those fat cells remain in the child's body throughout life. In adulthood, excess calories simply cause existing fat cells to get larger. What this means is that obesity in childhood is especially serious. In some studies, people who became obese as children had up to five times as many fat cells as those who became obese as adults.

Obesity can also be caused by certain medical conditions. For example, hypothyroidism (pronounced HI-po-THIE-roi-DIZ-uhm) is a condition in which the thyroid gland does not function normally. The thyroid gland is responsible for the body's general level of activity. In hypothyroidism, the body's overall level of activity is reduced, causing fewer calories to be burned. As a result, the body tends to gain weight.

Consumption of certain drugs can also result in obesity. Steroids and antidepressants are examples of such drugs.

SYMPTOMS


The major symptoms of obesity are excessive weight gain and the presence of large amounts of fatty tissue. Obesity can also give rise to several other conditions, including:

  • Arthritis (see arthritis entry) and other problems with bones and muscles, such as lower back pain
  • Heartburn
  • High cholesterol levels
  • High blood pressure
  • Menstrual problems
  • Shortness of breath
  • Skin disorders

DIAGNOSIS


Diagnosis of obesity is made by comparing the patient's weight with ideal weight charts. A direct measure of body fat can also be made with an instrument known as calipers. Calipers are a scissor-shaped device used to measure the thickness of a person's flesh at the back of the upper arm. This measurement can be used to tell whether a person has an excess of fatty tissue. Women whose body weight consists of more than 30 percent fatty tissue are regarded as obese. Men with 25 percent fatty tissue in their body weight are considered to be obese.

Doctors may also note the way in which a person's body fat is distributed. Some patterns of distribution are associated with certain complications of obesity. For example, a person who is "apple-shaped" has a higher risk of cancer, heart disease, and diabetes than someone who is "pear-shaped." An "apple-shaped" person is one whose weight is concentrated around the waist and abdomen. A "pear-shaped" person is one whose extra weight tends to be around the hips and thighs.

TREATMENT


Treatment of obesity depends on two factors: how overweight is a person and how good is his or her general health. The most important point is that to be successful, any treatment must effect lifelong, not short-term, changes. Many people try "yo-yo" dieting. Yo-yo dieting is a pattern in which a person tries some kind of diet for a few weeks or a few months and then quits the diet. Later on, the person tries the same diet again or a new one.

As a result, the person is constantly losing weight and then regaining it. This pattern can be very dangerous. A person who practices yo-yo dieting is more likely to develop fatal health problems than someone who lost the weight all at once and kept it off or someone who never lost the weight at all.

Effective treatment for obesity depends on a few general issues, such as:

  • What and how much a person eats. Patients are often asked to keep a food diary listing the foods they eat each day. Then they can analyze their diet to determine its nutritional value and the fat content of foods. The patient may be encouraged to change his or her grocery-shopping habits. For example, buying only the items on a shopping list prevents a person from buying other foods on impulse. Patients can also be taught to eat smaller, more frequent meals and to slow down the rate at which they eat during meals.
  • How a person responds to food. Patients can be taught that eating can reflect psychological issues. For example, a person under stress may bingethat is, eat large amounts of food at once. With this understanding, a person may be able to find other ways of dealing with emotional issues besides eating.
  • How they spend their time. Many obese people engage in little or no exercise. By making exercise a regular part of their lives, they may be able to lose weight and to keep it off. A variety of exercises can be tried so that the patient does not become bored with only one kind of activity.

For most individuals who are mildly obese, changes of this kind can be made with or without consulting a physician. Other mildly obese people may seek the help of a commercial weight-loss program, such as Weight Watchers. The success of such programs is difficult to measure, however. The programs themselves vary from the highly reputable to the less promising. Also, people tend to drop out of such programs quickly, so it is difficult to judge how effective any one program might be in helping a person lose weight.

Generally speaking, people should be cautious of programs that offer quick and easy results. Losing weight usually requires significant lifestyle changes, including diet and amount of exercise.

People who are moderately obese may require a higher level of professional help. A common approach is to recommend a balanced diet of no more than 1,500 calories per day. Less commonly, a doctor may recommend a verylow-calorie liquid protein diet. A diet of this kind provides no more than 700 calories a day and may be continued for up to three months. This kind of diet should not be confused with commercial liquid protein diets or commercial weight-loss shakes and drinks. Doctors design these diets for the specific needs of each individual patient.

Doctors may also recommend counseling for obese patients. Counseling sometimes helps people deal with psychological issues that lead to their weight-gain problems.

Dietary and lifestyle changes are useful with severely obese patients. But such patients may need even more aggressive treatment. For example, surgery may be performed to decrease the size of a person's stomach or small intestine. The purpose of this kind of surgery is to reduce the volume of food a person can eat.

Other forms of obesity surgery are sometimes performed. Liposuction, for example, is a procedure in which fat is removed from beneath the skin. Liposuction is of little or no value in solving a person's obesity problems. It may change his or her physical appearance, but it does not solve any of the underlying problems that lead to obesity in the first place.

Appetite-suppressant drugs are sometimes prescribed to aid in weight loss. These drugs work by increasing the level of certain chemicals that occur naturally in the brain, making a person feel full. Appetite suppressants can work on a short-term basis. That is, people are likely to lose weight while they are taking the drugs. But the drugs do not solve the basic problems that lead to obesity. When a person stops taking the drugs, his or her appetite returns. The person once again begins eating too much, and the weight returns.

Appetite suppressants are also of some concern because they may have harmful side effects and long-term effects that are not well understood. In November 1997, for example, the U.S. Food and Drug Administration removed a group of appetite-suppressant drugs from the market because they could cause potentially fatal heart defects.

The only weight-loss drug available without a prescription is phenyl-propanolamine (pronounced FEN-uhl-PRO-puh-NOL-uh-meen, trade names Acutrim, Dexatrim). This drug has been found to increase weight loss by a factor of about 5 percent. The problem is that the weight tends to return as soon as the drug is discontinued.

Some of the side effects that may accompany the use of weight-loss drugs include:

  • Constipation
  • Dry mouth
  • Headache
  • Irritability
  • Nausea
  • Nervousness
  • Sweating

Alternative Treatment

Some alternative forms of treatment for obesity have problems similar to those of drugs. For example, the Chinese herb ephedra has been recommended in a weight-loss program that also includes a low-fat diet and exercise. The herb does help a person lose weight on a short-term basis. But the weight tends to return when use of the herb is discontinued. In addition, large amounts of ephedra can produce a number of side effects, such as anxiety, irregular heartbeat, heart attack, high blood pressure, insomnia, irritability, nervousness, seizures, stroke, and even death.

Diuretic herbs have also been suggested for the treatment of obesity. A diuretic is a substance that increases the rate of urine output. As a person produces more urine, his or her weight decreases. However, once the herb is discontinued, urine production returns to normal, as does obesity.

Other natural remedies that have been suggested for weight loss include:

  • Red peppers and mustard, because they increase a person's metabolic rate (the rate at which food is digested). They also make a person thirsty, so he or she is more likely to drink water (which contains no calories) than to eat food.
  • Walnuts, because they increase the level of brain chemicals that tell a person he or she is no longer hungry.
  • Dandelion, because it increases the metabolic rate and decreases desire for sugary foods.

Acupressure and acupuncture are also said to decrease the desire for food. Acupuncture is a Chinese therapy that uses fine needles to pierce the body; acupressure involves applying pressure to certain points in the body. Mental techniques such as visualization and meditation may create a better self-image and decrease the need to overeat. Mental concentration, yoga, and similar techniques may provide similar benefits. In many cases, support groups can help a person deal with the problems that led to his or her obesity.

PROGNOSIS


Short-term diet programs are seldom successful. Studies show that 85 percent of dieters who do not exercise on a regular basis regain their lost weight within two years. Yo-yo dieting encourages the body to store fat and may increase the risk of heart problems. The only certain way to conquer obesity is to make fundamental changes in eating and exercise habits.

PREVENTION


The best way to prevent obesity is to avoid a high intake of fats. The National Cholesterol Education Program suggests that no more than 30 percent of the calories people eat should come from fats. A good way to monitor one's diet is to keep a detailed food diary. That way, one will know exactly how many calories are consumed in a day and where those calories come from.

A program of vigorous exercise is also very important. Activity is the only way that calories are used up. The more active a person is, the less likely that calories will be converted into fat.

Finally, children should learn early in their lives the value of a healthful diet and exercise. By controlling their intake of calories and planning activities that will burn them up, the problems of obesity can usually be avoided.

FOR MORE INFORMATION


Books

Gottlieb, Bill, ed. New Choices in Natural Healing. Emmaus, PA: Rodale Press, 1995.

Harris, Dan R., ed. Diet and Nutrition Sourcebook. Detroit: Omnigraphics, 1996.

Slupik, Ramona I., ed. American Medical Association Complete Guide to Women's Health. New York: Random House, 1996.

Organizations

HFC Nutrition Research Foundation, Inc. P.O. Box 22124, Lexington, KY 40522. (606) 276-3119.

National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. 2 Information Way, Bethesda, MD 20892-3570. http://www.niddk.nih.gov.

National Obesity Research Foundation. Temple University, Weiss Hall 867, Philadelphia, PA 19122.

The Weight-Control Information Network. 1 Win Way, Bethesda, MD 20896-3665. (301) 951-1120.

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Obesity

Obesity

What Happens to People with Obesity?

Is It Possible to Be Fit, Fat, and Happy?

Resources

Obesity (o-BEE-si-tee) is a significant excess of body fat. Children with obesity are at higher risk for obesity when they grow up. Adults with obesity are at higher risk for high blood pressure, diabetes, and other health problems. In cultures that value being thin, people with obesity also may experience emotional distress as well.

KEYWORDS

for searching the Internet and other reference sources

Adipose

Bariatrics

Binge eating disorder

Body mass index

Diet

Morbid obesity

Nutrition

Weight control

Body Mass Index

Body mass index (BMI) is a mathematical formula that doctors and dietitians use to measure whether people are at a healthy weight relative to their height.It is based on weight measured in kilograms and height measured in meters: BMI = kg/m2. BMI charts classify adult obesity in ranges; for example:

  • BMIs 1921: lean people, such as marathon runners
  • BMIs 2224: people of average weight
  • BMIs 2529: people who are muscular or mildly overweight
  • BMIs 3035: people who are overweight and who are at significantly higher risk for health problems
  • BMIs >40: people with severe obesity who are at very high risk for health problems.

Although BMI tends to reflect how much fat a person has, it does not measure body fatness directly. For example, a muscular athlete might have a higher than average weight and BMI measurement despite having a lower than average amount of body fat.

Prevalence rates for obesity are on the rise in the United States and in other parts of the developed world where lifestyles make it easy for people to take in more calories than their bodies use. How do people take in too many calories? Try fast-food burgers and fries, supersize colas, chips, dips, and nachos. How do people use too few calories? Try car rides instead of walking or riding a bike, and television and video games instead of sports. The result? Chubby couch potatoes who are banking extra deposits of adipose (fatty) tissue.

Lifestyle is not the only cause of obesity. Researchers believe that genes and heredity also play a very important role in many cases. People with a history of obesity in one or both parents are at higher risk of becoming obese themselves. People who have inherited obesity genes may use calories at a slower rate than others, or they may not have the same appetite shutoff control system that helps lean people stop eating when they have taken in enough calories. Also, people who become obese as children may increase the total number of fat cells in their bodies, making it much more likely that they will be obese as adults.

What Happens to People with Obesity?

Children

Children who weigh more than 20 percent more than they should for their height and age may be considered overweight, and those who weigh more than 30 percent more may be considered obese. Diets that severely restrict calorie intake often are not a good idea for children because of their need for energy to support normal growth, but doctors may suggest that overweight children be offered fewer calorie-laden foods and find ways to become more physically active after school and on weekends. Certainly they are likelier than normal-weight children to have problems with their peers. They may have trouble keeping up with other kids in sports and other activities, they may tire and get out of breath more quickly, and they may be called cruel names.

Teens

Teenagers with obesity may have the same problems as obese children, but they also may start having aches and pains as the extra fat in their bodies stresses their joints and overloads their muscles and tendons. Obese teens, as well as some younger children, sometimes may begin to show some of the health problems commonly seen in obese adults such as high blood pressure and diabetes. Also, they may have less active dating and social lives, and they may be at risk for binge eating disorder.

Rx: Weight Loss

The weight-loss industry is a big business, including over-the-counter medications such as Metabolife and organizations such as Weight Watchers. Unfortunately, many media-promoted weight-loss products and programs are based on fads or gimmicks that raise false hopes but have not been shown to produce long-term improvements in weight. Experts stress that weight loss produced by crash dieting is almost never sustained unless a person learns to permanently modify eating and exercise habitsand those lifestyle changes are difficult to maintain.

There are also prescription medications for weight loss, presently approved only for treatment of severely obese adults:

  • Orlistat (Xenical) reduces the bodys ability to absorb fat that has been eaten. However, it also can interfere with the absorption of vitamins, and may cause oily or fatty bowel movements.
  • Subutramine (Meridia) is an appetite suppressant that affects the bodys brain chemistry. It is not recommended for people with high blood pressure, heart disease, or risk of stroke.

Binge eating disorder

Binge eating disorder also is known as compulsive overeating. Like other eating disorders, it often involves feelings of anxiety, stress, anger, being out of control during a binge, and being remorseful after a binge. It also may involve hiding food and secret eating, behaviors that interfere with social activities. Eventually, it may lead to obesity, still another cause of stress in a culture that seems to believe a person can never be too thin.

Adults

In addition to aches and pains and physical limitations, obese adults face a higher risk of a number of health problems, including high blood pressure, diabetes, heart disease, and stroke. They may face discrimination when they apply for jobs or promotions, and studies have shown that they may be unfairly viewed by others as lazy or less intelligent. Adults with obesity often experience the inconvenience and frustration of needing large-size clothing, large-size movie seats and airplane seats, and large-size seat belts in a world designed by and for medium-size people.

Severe obesity

Severe obesity also is called morbid obesity because it is so frequently accompanied by serious health complications. People with severe obesity almost always experience problems with everyday living. They may have trouble walking or exercising, they may have difficulty breathing while they sleep (sleep apnea), and they may be treated with a prescription medication or gastric (stomach) surgery to help bring their weight down to a healthier level.

Is It Possible to Be Fit, Fat, and Happy?

Yes, it is, and there are many media role models showing how, including weightlifter Cheryl Haworth, model Emme, and actress Camryn Manheim. Working with peer support groups and therapists can help people learn ways to resist the stigma attached to being fat in a culture that values thinness. Working with psychotherapists can help people with binge eating disorder learn healthier ways to cope with anxiety and stress. Working with medical doctors can help people with severe obesity get treatment for related health problems, such as high blood pressure or sleep apnea, and it also can help them decide whether prescription medications or surgery are appropriate treatments. Eating a balanced diet can benefit everyone. And getting lots of physical activity can make anyone fitter and happier, no matter how fat or thin the person is.

See also

Anorexia

Body Image

Bulimia

Eating Disorders

Genetics and Behavior

Therapy

Resources

Organizations

American Society of Bariatric Physicians, 5600 South Quebec Street, Suite 109A, Englewood, CO 80111. This group is a national professional society for physicians who specialize in the medical treatment of obesity and related conditions. Telephone 303-779-4833 (for referral to a physician) http://www.asbp.org

KidsHealth.org. The medical experts at the Nemours Foundation in Wilmington, Delaware, post fact sheets on their website for children, teens, and parents covering obesity, body mass index, eating disorders, activity patterns for children and teens, and other topics. http://www.KidsHealth.org

Overeaters Anonymous, 6075 Zenith Court Northeast, Rio Rancho, NM 87124. This network of peer support groups helps people find local meetings that use fellowship and a 12-step technique for lifelong control of binge eating disorder. Telephone 505-891-2664 http://www.overeatersanonymous.org

Weight-Control Information Network (WIN), 1 WIN Way, Bethesda, MD 20892-3665. This division of the U.S. National Institute for Diabetes and Digestive and Kidney Diseases provides information about obesity, weight control, nutrition, weight-loss medications, and gastric surgery. Telephone 877-946-4627 http://www.niddk.nih.gov/health/nutrit/nutrit.htm

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obesity

obesity Excessive accumulation of body fat. A body mass index above 30 is considered to be obesity (and above 40 gross obesity). The desirable range of BMI for optimum life expectancy is 20–25; between 25 and 30 is considered to be overweight rather than obesity. People more than 50% above desirable weight are twice as likely to die prematurely as those within the desirable weight range.

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DAVID A. BENDER. "obesity." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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DAVID A. BENDER. "obesity." A Dictionary of Food and Nutrition. 2005. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O39-obesity.html

obesity

obesity Condition of being overweight, generally defined as weighing 20% or more above the recommended norm for the person's sex, height, and build. People who are overweight are at increased risk of disease and have a shorter life expectancy than those of normal weight.

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obesity

obesity (oh-beess-iti) n. the condition in which excess fat has accumulated in the body, mostly in the subcutaneous tissues. Clinical obesity is considered to be present when a person has a body mass index of 30 or over. See also leptin.
obese adj.

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obesity

obesitybanditti, bitty, chitty, city, committee, ditty, gritty, intercity, kitty, nitty-gritty, Pitti, pity, pretty, shitty, slitty, smriti, spitty, titty, vittae, witty •fifty, fifty-fifty, nifty, shifty, swiftie, thrifty •guilty, kiltie, silty •flinty, linty, minty, shinty •ballistae, Christie, Corpus Christi, misty, twisty, wristy •sixty •deity, gaiety (US gayety), laity, simultaneity, spontaneity •contemporaneity, corporeity, femineity, heterogeneity, homogeneity •anxiety, contrariety, dubiety, impiety, impropriety, inebriety, notoriety, piety, satiety, sobriety, ubiety, variety •moiety •acuity, ambiguity, annuity, assiduity, congruity, contiguity, continuity, exiguity, fatuity, fortuity, gratuity, ingenuity, perpetuity, perspicuity, promiscuity, suety, superfluity, tenuity, vacuity •rabbity •improbity, probity •acerbity • witchetty • crotchety •heredity •acidity, acridity, aridity, avidity, cupidity, flaccidity, fluidity, frigidity, humidity, hybridity, insipidity, intrepidity, limpidity, liquidity, lividity, lucidity, morbidity, placidity, putridity, quiddity, rabidity, rancidity, rapidity, rigidity, solidity, stolidity, stupidity, tepidity, timidity, torpidity, torridity, turgidity, validity, vapidity •commodity, oddity •immodesty, modesty •crudity, nudity •fecundity, jocundity, moribundity, profundity, rotundity, rubicundity •absurdity • difficulty • gadgety •majesty • fidgety • rackety •pernickety, rickety •biscuity •banality, duality, fatality, finality, ideality, legality, locality, modality, morality, natality, orality, reality, regality, rurality, tonality, totality, venality, vitality, vocality •fidelity •ability, agility, civility, debility, docility, edibility, facility, fertility, flexility, fragility, futility, gentility, hostility, humility, imbecility, infantility, juvenility, liability, mobility, nihility, nobility, nubility, puerility, senility, servility, stability, sterility, tactility, tranquillity (US tranquility), usability, utility, versatility, viability, virility, volatility •ringlety •equality, frivolity, jollity, polity, quality •credulity, garrulity, sedulity •nullity •amity, calamity •extremity • enmity •anonymity, dimity, equanimity, magnanimity, proximity, pseudonymity, pusillanimity, unanimity •comity •conformity, deformity, enormity, multiformity, uniformity •subcommittee • pepperminty •infirmity •Christianity, humanity, inanity, profanity, sanity, urbanity, vanity •amnesty •lenity, obscenity, serenity •indemnity, solemnity •mundanity • amenity •affinity, asininity, clandestinity, divinity, femininity, infinity, masculinity, salinity, trinity, vicinity, virginity •benignity, dignity, malignity •honesty •community, immunity, importunity, impunity, opportunity, unity •confraternity, eternity, fraternity, maternity, modernity, paternity, taciturnity •serendipity, snippety •uppity •angularity, barbarity, bipolarity, charity, circularity, clarity, complementarity, familiarity, granularity, hilarity, insularity, irregularity, jocularity, linearity, parity, particularity, peculiarity, polarity, popularity, regularity, secularity, similarity, singularity, solidarity, subsidiarity, unitarity, vernacularity, vulgarity •alacrity • sacristy •ambidexterity, asperity, austerity, celerity, dexterity, ferrety, posterity, prosperity, severity, sincerity, temerity, verity •celebrity • integrity • rarity •authority, inferiority, juniority, majority, minority, priority, seniority, sonority, sorority, superiority •mediocrity • sovereignty • salubrity •entirety •futurity, immaturity, impurity, maturity, obscurity, purity, security, surety •touristy •audacity, capacity, fugacity, loquacity, mendacity, opacity, perspicacity, pertinacity, pugnacity, rapacity, sagacity, sequacity, tenacity, veracity, vivacity, voracity •laxity •sparsity, varsity •necessity •complexity, perplexity •density, immensity, propensity, tensity •scarcity • obesity •felicity, toxicity •fixity, prolixity •benedicite, nicety •anfractuosity, animosity, atrocity, bellicosity, curiosity, fabulosity, ferocity, generosity, grandiosity, impecuniosity, impetuosity, jocosity, luminosity, monstrosity, nebulosity, pomposity, ponderosity, porosity, preciosity, precocity, reciprocity, religiosity, scrupulosity, sinuosity, sumptuosity, velocity, verbosity, virtuosity, viscosity •paucity • falsity • caducity • russety •adversity, biodiversity, diversity, perversity, university •sacrosanctity, sanctity •chastity •entity, identity •quantity • certainty •cavity, concavity, depravity, gravity •travesty • suavity •brevity, levity, longevity •velvety • naivety •activity, nativity •equity •antiquity, iniquity, obliquity, ubiquity •propinquity

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