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Weight Management

Weight management


Definitions

Weight management refers to a set of practices and behaviors that are necessary to keep one's weight at a healthful level. It is preferred to the term "dieting," because it involves more than regulation of food intake or treatment of overweight people. People diagnosed with eating disorders who are not obese or overweight still need to practice weight management. Some health care professionals use the term "nutritional disorders" to cover all disorders related to weight.

The term "weight management" also reflects a change in thinking about treatment of obesity and overweight during the past 20 years. Before 1980, treatment of overweight people focused on weight loss, with the goal of helping the patient reach an "ideal weight" as defined by standard life insurance height-weight charts. In recent years, however, researchers have discovered that most of the negative health consequences of obesity are improved or controlled by a relatively modest weight loss, perhaps as little as 10% of the patient's body weight. It is not necessary for the person to reach the "ideal" weight to benefit from weight management. Some nutritionists refer to this treatment goal as the "10% solution." Secondly, the fact that most obese people who lose large amounts of weight from reduced-calorie diets regain it within five years has led nutrition experts to emphasize weight management rather than weight loss as an appropriate outcome of treatment.


Overweight and obese

Overweight and obese are not the same thing. People who are overweight weigh more than they should compared with set standards for their height. The excess weight may come from muscle tissue, body water, or bone, as well as from fat. A person who is obese has too much fat in comparison to other types of body tissue; hence, it is possible to be overweight without being obese.

There are several ways to determine whether someone is obese. Some measures are based on the relationship
between the person's height and weight. The older measurements of this correlation are the so-called height-weight tables that list desirable weights for a given height. A more accurate measurement of obesity is body mass index, or BMI. The BMI is an indirect measurement of the amount of body fat. The BMI is calculated in English measurements by multiplying a person's weight in pounds by 703.1, and dividing that number by the person's height in inches squared. A BMI between 19 and 24 is considered normal; 2529 is overweight; 3034 is moderately obese; 3539 is severely obese; and 40 or higher is defined as morbidly obese. More direct methods of measuring body fat include measuring the thickness of the skin fold at the back of the upper arm, and bioelectrical impedance analysis (BIA). Bioelectrical impedance analysis measures the total amount of water in the body using a special instrument that calculates the different degrees of resistance to an electrical current in different types of body tissue. Fatty tissue has a higher resistance to the current than body tissues containing larger amounts of water. A higher percentage of body water indicates a greater amount of lean tissue.


Eating disorders

Eating disorders are a group of psychiatric disturbances defined by unhealthy eating or weight management practices. Anorexia nervosa is an eating disorder in which persons restrict their food intake severely, refuse to maintain a normal body weight, and express intense fear of becoming obese. Bulimia nervosa is a disorder marked by episodes of binge eating followed by attempts to avoid weight gain from the food by abusing laxatives , forcing vomiting, or overexercising. A third type, binge eating disorder, is found in some obese people, as well as in people of normal weight. In binge eating disorder, the person has an eating binge but does not try to get rid of the food after eating it. Although most patients diagnosed with anorexia or bulimia are women, 40% of patients with binge eating disorder are men.


Purpose

The purpose of weight management is to help each patient achieve and stay at the best weight possible the context of overall health, occupation, and living situation. A second purpose is the prevention and treatment of diseases and disorders associated with obesity or with eating disorders. These disorders include depression and other psychiatric disturbances, in addition to the physical problems associated with nutritional disorders.


Demographics and statistics

Obesity has become a major public health concern in the United States in the last decade. As of 2003, obesity ranks second only to smoking as a major cause of preventable deaths. It is estimated that 300,000 people die in the United States each year from weight-related causes. The proportion of overweight adults in the general population has continued to rise since the 1960s. About 34% of American adults, or 58 million people, are overweight, compared with 25% in 1980. In addition, there has been a 42% increase in the rate of childhood obesity since 1980.

The prevalence of obesity in the United States varies somewhat according to sex, age, race, and socioeconomic status. Among adults, 35% of women are considered obese, compared to 31% of men. The rate of obesity increases as people get older; those aged 55 or older are more than twice as likely to be obese as those in their twenties. African American men have the same rate of obesity as Caucasian men; however, African American women are almost twice as likely as Caucasian women to be obese by the time they reach middle age. The same ratio holds true for socioeconomic status; people in the lowest third of the income and educational level distribution are twice as likely to be obese as those with more education and higher income.

From the economic standpoint, obesity costs the United States over $100 billion each year. This amount includes the direct costs of hospital care and medical services, which come to $45.8 billion annually, or 6.8% of all health care costs. Another $18.9 billion represents the indirect costs of obesity, such as disabilities related to overweight or work days lost to obesity-related illnesses.

Obesity is considered responsible for:

  • 8897% of cases of type 2 diabetes
  • 5770% of cases of coronary heart disease
  • 70% of gallstone attacks
  • 35% of cases of hypertension
  • 11% of breast cancers
  • 10% of colon cancers

In addition, obesity intensifies the pain of osteoarthritis and gout; increases the risk of complications in pregnancy and childbirth; contributes to depression and other mental disorders; and makes a person a poor candidate for surgery. Many surgeons refuse to operate on patients who weigh more than 300 lb (136 kg).

Although fewer people suffer from eating disorders than from obesity, the National Institutes of Mental Health (NIMH) reports that 10 million adults in the United States meet the diagnostic criteria for anorexia or bulimia. Although eating disorders are stereotyped as affecting only adolescent or college-aged women, as of 2003 at least 10% of people with eating disorders are malesand the proportion of males to females is rising. Moreover, the number of women over 45 years of age who are diagnosed with eating disorders is also rising; many doctors attribute this startling new trend to fear of aging, as well as fear of obesity.

The long-term health consequences of eating disorders include gum disease and loss of teeth, irregular heart rhythm, disturbances in the chemical balance of the blood, and damage to the digestive tract. At least 50,000 people die each year in the United States as the direct result of an eating disorder; anorexia is the leading cause of death in women between the ages of 17 and 25.


Description

To understand the goals and structure of nutritionally sound weight management programs, it is helpful to look first as the causes of being overweight, obesity, and eating disorders.


Causes of nutrition-related disorders


genetic/biologic. Studies of twins separated at birth and research with genetically altered mice have shown that there is a genetic component to obesity. Some researchers think that there are also genetic factors involved in eating disorders.

lifestyle-related. The ready availability of relatively inexpensive, but high-caloric snacks and "junk food" is considered to contribute to the high rates of obesity in developed countries. In addition, the fast pace of modern life encourages people to select quick-cooking processed foods that are high in calories, rather than making meals that are more healthful but take longer to prepare. Lastly, changes in technology and transportation patterns mean that people today do not do as much walking or hard physical labor as earlier generations did. This sedentary, or inactive lifestyle makes it easier for people to gain weight.

sociocultural. In recent years, many researchers have examined the role of advertising and the mass media in encouraging unhealthy eating patterns. On the one hand, advertisements for such items as fast food, soft drinks, and ice cream, often convey the message that food can be used to relieve stress, reward, or comfort oneself, or substitute for a fulfilling human relationship. On the other hand, the media also portray unrealistic images of human physical perfection. Their emphasis on slenderness as essential to beauty, particularly in women, is often cited as a major factor in the increase of eating disorders over the past three decades.

Another sociocultural factor that contributes to obesity among some Hispanic and Asian groups is the belief that children are not healthy unless they look plump. Overfeeding in infancy and early childhood, unfortunately, makes weight management in adolescence and adult life much more difficult.


medications. Recent research has found that a number of prescription medications can contribute to weight gain. These drugs include steroid hormones, antidepressants, benzodiazepine tranquilizers, lithium, and antipsychotic medications.



Aspects of weight management

Since the late 1980s, nutritionists and health care professionals had come to recognize that successful weight management programs have three characteristics, as follows:

  • They present weight management as a lifetime commitment to healthful patterns of eating and exercise , rather than emphasize strict dieting alternating with carelessness about eating habits.
  • They are tailored to each person's age, general health, living situation, and other individual characteristics.
  • They recognize that the emotional, psychological, and spiritual facet of human life are as important to maintaining a healthy lifestyle as the medical and nutritional facets.

Nutrition

The nutritional aspect of weight management programs includes education about healthful eating, as well as modifying the person's food intake.


dietary regulation. Most weight-management programs are based on a diet that supplies enough vitamins and minerals; 5063 grams of protein each day; an adequate intake of carbohydrates (100 g) and dietary fiber (2030 g); and no more than 30% of each day's calories from fat. Good weight-management diets are intended to teach people how to make wise food choices and to encourage gradual weight loss. Some diets are based on fixed menus, while others are based on food exchanges. In a food-exchange diet, a person can choose among several items within a particular food group when following a menu plan. For example, if a person's menu plan allows for two items from the vegetable group at lunch, they can have one raw and one cooked vegetable, or one serving of vegetable juice along with another vegetable. More detailed information about these and other weight-management diets is available in a booklet from the Weight Information Network of the National Institutes of Health, called Weight Loss for Life, listed under "Resources" below.

nutritional education. Nutritional counseling is important to successful weight management because many people, particularly those with eating disorders, do not understand how the body uses food. They may also be trying to manage their weight in unhealthy ways. One recent study of adolescents found that 32% of the females and 17% of the males were using such potentially dangerous methods of weight control as smoking, fasting, over-the-counter diet pills, or laxatives.


Exercise

Regular physical exercise is a major part of weight management because it increases the number of calories used by the body and because it helps the body to replace fat with lean muscle tissue. Exercise also serves to lower emotional stress levels and to promote a general sense of well-being. People should consult a doctor before beginning an exercise program, however, to make sure that the activity that interests them is safe relative to any other health problems they may have. For example, people with osteoarthritis should avoid high-impact sports that are hard on the knee and ankle joints. Good choices for most people include swimming, walking, cycling, and stretching exercises.


Psychological/psychiatric

Both obesity and eating disorders are associated with a variety of psychiatric disorders, most commonly major depression and substance abuse. Almost all obese people feel harshly judged and criticized by others, and fear of obesity is a major factor in the development of both anorexia and bulimia. Many people find medications and/or psychotherapy to be a helpful part of a weight management program.

medications. In recent years, doctors have been cautious about prescribing appetite suppressants, which are drugs given to reduce the desire for food. In 1997, the Food and Drug Administration (FDA) banned the sale of two drugs: fenfluramine (known as "fen-phen") and phentermine when they were discovered to cause damage to heart valves. A newer appetite suppressant, known as sibutramine, has been approved as safe. Another new drug that is sometimes prescribed for weight management is called orlistat. It works by lowering the amount of dietary fat that is absorbed by the body. However, it can cause significant diarrhea.

People with eating disorders are sometimes given antidepressant medications, most often fluoxetine (Prozac) or venlafaxine, to relieve the symptoms of depression or anxiety that often accompany eating disorders.

cognitive-behavioral therapy. Cognitive-behavioral therapy (CBT) is a form of psychotherapy that has been shown to be effective in reinforcing the changes in food selection and eating patterns that are necessary to successful weight management. In this form of therapy, patients learn to modify their eating habits by keeping diaries and records of what they eat, what events or feelings trigger overeating, and any other patterns that they notice about their choice of foods or eating habits. They also examine their attitudes toward food and weight management, and work to change any attitudes that are self-defeating or interfere with a healthy lifestyle. Most CBT programs also include nutritional education and counseling.

weight-management groups. Many doctors and nutritional counselors suggest that patients attend a weight-management group for social support. Social support is essential in weight management, because many who suffer from obesity or an eating disorder struggle with intense feelings of shame. Many isolate themselves from others because they are afraid of being teased or criticized for their appearance. Such groups as Overeaters Anonymous (OA) or Take Off Pounds Sensibly (TOPS) help members in several ways: They help to reduce the levels of shame and anxiety that most members feel; they teach strategies for coping with setbacks in weight management; they provide settings for making new friends; and they help people learn to handle problems in their workplace or in relationships with family members.

Surgical

As of 2003, bariatric surgery is the most successful approach to weight management for people who are morbidly obese (BMI of 40 or greater), or severely obese with additional health complications. Surgical treatment of obesity usually results in a large weight loss that is successfully maintained for longer than five years. The most common surgical procedures for weight management are vertical banded gastroplasty (VBG), sometimes referred to as "stomach stapling," and gastric bypass . Vertical banded gastroplasty works by limiting the amount of food the stomach can hold, while gastric bypass works by preventing normal absorption of the nutrients in the food.


Complementary and alternative medicine (CAM) approaches

Some forms of complementary and alternative medicine are beneficial additions to weight management programs.

movement therapies. Movement therapies include a number of forms of exercise, such as tai chi, yoga, dance therapy, Trager work, and the Feldenkrais method. Many of these approaches help people improve their posture and move their bodies more easily as well as keeping active. Tai chi and yoga, for example, are good for people who must avoid high-impact physical workouts. Yoga can also be adapted to a person's individual needs or limitations with the help of a qualified teacher following a doctor's recommendations. Books and videos on yoga and weight management are available through most bookstores or the American Yoga Association.

spiritual and religious practice. Prayer, meditation, and regular religious worship have been linked to reduced emotional stress in people struggling with weight issues. In addition, many people find that spiritual practice helps them to keep a healthy perspective on weight management, so that it does not crowd out other important interests and concerns in their lives.

herbal preparations. The one type of alternative treatment that people should be extremely cautious about making part of a weight management program is over-the-counter herbal preparations advertised as "fat burners," muscle builders, or appetite suppressants. Within a two-week period in early 2003, the national media carried accounts of death or serious illness from taking these substances. One is ephedra, a herb used in traditional Chinese medicine that can cause strokes, heart attacks, seizures, and psychotic episodes. The other is usnic acid, a compound derived from lichens that can cause liver damage.


Normal results

As of 2003, much more research needs to be done to improve the success of weight management programs. A position paper published by the American Dietetic Association in the summer of 2002 summarizes the present situation: "Although our knowledge base has greatly expanded regarding the complex causation of increased body fat, little progress has been made in long-term maintenance interventions, with the exception of surgery." Most adults in weight maintenance programs find it difficult to change eating patterns learned over a lifetime. Furthermore, their efforts are all too often undermined by friends or relatives, as well as by media messages that encourage overeating or the use of food as a mood-enhancing drug. More effective weight maintenance programs may well depend on broad-based changes in society.

Resources

books

american psychiatric association. "eating disorders." in diagnostic and statistical manual of mental disorders, 4th edition, text revision. washington, dc: american psychiatric association, 2000.

brownell, kelly, ph.d., and judith rodin, ph.d. the weight maintenance survival guide. dallas, tx: brownell & hager publishing co., 1990.

flancbaum, louis, m.d., with erica manfred and deborah biskin. the doctor's guide to weight loss surgery. west hurley, ny: fredonia communications, 2001.

hornbacher, marya. wasted: a memoir of anorexia and bulimia. new york: harper perennial editions, 1999.

" nutritional disorders: obesity." section 1, chapter 5 in the merck manual of diagnosis and therapy, edited by mark h. beers, m.d., and robert berkow, m.d. whitehouse station, nj: merck research laboratories, 1999.

pelletier, kenneth r., m.d. "cam therapies for specific conditions: obesity." in the best alternative medicine, part ii. new york: simon & schuster, 2002.


periodicals

bellafante, ginia. " when midlife seems just an empty plate." new york times, march 9, 2003 [cited march 12, 2003]. <www.nytimes.com/2003/03/09/health.html>.

chass, murray. "pitcher's autopsy points to ephedra as one factor." new york times, march 14, 2003 [cited march 14, 2003]. <www.nytimes.com/2003/03/14/sports/baseball/14base.html>.

cummings, s., e. s. parham, and g. w. strain. "position of the american dietetic association: weight management." journal of the american dietetic association 102 (august 2002): 1145-1155.

davis, r. b., and l. w. turner. "a review of current weight management: research and recommendations." journal of the american academy of nurse practitioners 13 (january 2001): 15-19.

drohan, s. h. "managing early childhood obesity in the primary care setting: a behavior modification approach." pediatric nursing 28 (november-december 2002): 599-610.

grady, denise. "seeking to shed fat, she lost her liver." new york times, march 4, 2003 [cited march 4, 2003]. <www.nytimes.com/2003/03/04/health.html>.

hanif, m. w., and s. kumar. "pharmacological management of obesity." expert opinion on pharmacotherapy 3 (december 2002): 1711-1718.

lowry, r., d. a. galuska, j. e. fulton, et al. "weight management goals and practices among u. s. high school students: associations with physical activity, diet, and smoking." journal of adolescent health 31 (august 2002): 133-144.

malhotra, s., k. h. king, j. a. welge, et al. "venlafaxine treatment of binge-eating disorder associated with obesity: a series of 35 patients." journal of clinical psychiatry 63 (september 2002): 802-806.

riebe, d., g. w. greene, l. ruggiero, et al. "evaluation of a healthy-lifestyle approach to weight management." preventive medicine 36 (january 2003): 45-54.


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 yoga association. <www.americanyogaassociation.org>.

overeaters anonymous (oa). world service office, p. o. box 44020, rio rancho, nm 87174-4020. (505) 891-2664. <www.oa.org>.

shape up america! c/o webfront solutions corporation, 15757 crabbs branch way, rockville, m. d. 20855. (301) 258-0540. <www.shapeup.org>.

weight-control information network (win). 1 win way, bethesda, md 20892-3665. (202) 828-1025 or (877) 946-4627.


other

national institutes of health, national institute of diabetes & digestive & kidney diseases (niddk). choosing a safe and successful weight-loss program. bethesda, md: niddk, 1998. nih publication no. 94-3700.

national institutes of health, national institute of diabetes & digestive & kidney diseases (niddk). do you know the health risks of being overweight? bethesda, md: niddk, 2001. nih publication no. 98-4098.

national institutes of health, national institute of diabetes & digestive & kidney diseases (niddk). weight loss for life. bethesda, md: niddk, 2002. nih publication no. 98-3700.


Rebecca Frey, Ph.D.

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Frey, Rebecca. "Weight Management." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Encyclopedia.com. 29 May. 2016 <http://www.encyclopedia.com>.

Frey, Rebecca. "Weight Management." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Encyclopedia.com. (May 29, 2016). http://www.encyclopedia.com/doc/1G2-3406200486.html

Frey, Rebecca. "Weight Management." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Retrieved May 29, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3406200486.html

Weight Loss

Weight loss

Definition

Weight loss is a reduction in body mass characterized by a loss of adipose tissue (body fat) and skeletal muscle.

Description

Unintentional weight loss is the most common symptom of cancer and often a side effect of cancer treatments. A poor response to cancer treatments, reduced quality of life, and shorter survival time may result from substantial weight loss. The body may become weaker and less able to tolerate cancer therapies. As body weight decreases, body functionality declines and may lead to malnutrition, illness, infection, and perhaps death.

Severe malnutrition is typically defined in two ways: functionally (increased risk of morbidity and/or mortality) and by degree of weight loss (greater than 2% per week, 5% per month, 7.5% per 3 months, and 10% per 6 months). Without considering a specific time course, grading is as follows:

  • Grade 0 = less than 5.0% weight loss
  • Grade 1 = 5.0% to 9.9%
  • Grade 2 = 10.0% to 19.9%
  • Grade 3 = greater than 20.0%
  • Grade 4 (life-threatening) is not specifically defined. Paying attention to weight loss at an early stage is necessary to prevent deterioration of weight, body composition, and performance status.

Causes

There are many reasons for weight loss in cancer patients, including appetite loss because of the effect of cancer treatments (chemotherapy , radiation therapy , or biological therapy) or due to psychological factors such as depression . Patients may suffer from anorexia and lose desire to eat, and thus consume less energy. When inadequate calories are consumed, it can lead to "wasting" of body stores (muscle and adipose tissue). Weight loss may be temporary or may continue at a life-threatening pace.

Weight loss may be also be a consequence of an increased requirement for calories (energy) due to infection, fever , or the effects of the tumor or cancer treatments. If infection or fever is present, it is necessary to consider that there is an increased caloric need of approximately 10% to 13% per degree above 98.6°F (37°C). Therefore, energy intake has to be increased to account for this rise in body temperature.

Weight loss may be a result of a common problem in cancer called cachexia. Approximately half of all cancer patients experience cachexia, a wasting syndrome that induces metabolic changes leading to a loss of muscle and fat. It has been proposed that cachexia may be due to the effects of the tumor, but this is debatable considering some patients with very large tumors do not experience cachexia, while others do even though tumors are less than 0.01% of body mass. Cachexia is most common in patients with pancreatic and gastric cancer. Approximately 83% to 87% of these patients experience weight loss. Cachexia is characterized by symptoms such as a decreased appetite, fatigue , and poor performance status. It can occur in individuals who consume enough food, but due to disease complications, cannot absorb enough nutrients (i.e. fat malabsorption). Although energy expenditure is sometimes increased, cachexia can occur even with normal energy expenditure. Cachexia is multifactorial in nature and associated with mechanical factors, psychological factors, changes in taste, and cytokines. It should be distinguished from anorexia, where there is a loss of desire to eat, resulting in weight loss. Cachexia is serious in cancer patients, sometimes leading to death.

Special concerns

In order to allow normal tissue repair following aggressive cancer therapies, patients require adequate calories and macronutrients in the form of protein, carbohydrates, and fat. Inadequate consumption of food and/or poor nutrition may impair the ability of a patient to tolerate a specific therapy. If a low tolerance to therapy necessitates a decrease in dose, the therapy's effectiveness could be compromised. Wound healing may also be impaired with poor nutrition and inadequate energy intake.

Research has demonstrated that men often experience significantly more weight loss than women over the course of the disease and lose weight much faster. On average, survival time for men is shorter than for women. Significant predictors of patient survival are stage of disease, initial weight-loss rate, and gender.

Treatments

Nutritional problems related to side effects should be addressed to ensure adequate nutrition and prevent weight loss. In particular, cancer patients should maintain an adequate intake of calories and protein to prevent protein-calorie malnutrition. The patient's caloric requirements can be calculated by a dietitian or doctor since nutrient requirements vary considerably from patient to patient.

The following dietary tips may help to reduce weight loss:

  • Eat more when feeling the hungriest.
  • Eat foods that are enjoyed the most.
  • Eat several small meals and snacks instead of three large meals. A regular meal schedule should be kept so meals are not missed.
  • Have ready-to-eat snacks on hand such as cheese and crackers, granola bars, muffins, nuts and seeds, canned puddings, ice cream, yogurt, and hard boiled eggs.
  • Eat high-calorie foods and high-protein foods.
  • Take a small meal as to enjoy the satisfaction of finishing a meal. Have seconds if still hungry.
  • Eat in a pleasant atmosphere with family and friends if desired.
  • Make sure to consume at least eight to ten glasses of water per day to maintain fluid balance.
  • Consider commercial liquid meal replacements such as Ensure, Boost, Carnation, and Sustacal.

An appetite stimulant may be given in order to prevent further weight loss such as megestrol acetate or dexamethasone . In clinical trials , both these medications appear to have similar and effective appetite stimulating effects with megestrol acetate having a slightly better toxicity profile. Fluoxymesterone has shown inferior efficacy and an unfavorable toxicity profile.

Alternative and complementary therapies

Depression may affect approximately 15% to 25% of cancer patients, particularly if the prognosis for recovery is poor. If anorexia is due to depression, there are antidepressant choices available through a physician. Counseling may be also be sought through a psychologist or psychiatrist to cope with depression.

It is important to check with a dietitian or doctor before taking nutritional supplements or alternative therapies because they may interfere with cancer medications or treatments. St. John's Wort has been used as a herbal remedy for treatment of depression, but it and prescription antidepressants is a dangerous combination that may cause symptoms such as nausea, weakness, and may cause one to become incoherent.

See Also Taste alteration

Resources

BOOKS

Keane, Maureen, et al. What to Eat If You Have Cancer: A Guide to Adding Nutritional Therapy to Your Treatment Plan. Lincolnwood, IL: National Textbook Company/Contemporary Publishing Group, 1996.

Nixon, Daniel W., M.D., Jane A. Zanca, and Vincent T. DeVitaThe Cancer Recovery Eating Plan: The Right Foods to Help Fuel Your Recovery. New York: Times Books, 1996.

Quillin, Patrick, and Noreen Quillin. Beating Cancer With NutritionRevised. Sun Lakes, AZ: Bookworld Services, 2001.

PERIODICALS

Kant, Ashima, et al. "A Prospective Study of Diet Quality and Mortality in Women." JAMA 283, no. 16 (2000): 2109-15.

Loprinzi, C.L., et al. "Randomized Comparison of Megestrol Acetate Versus Dexamethasone Versus Fluoxymesteronefor the Treatment of Cancer Anorexia/Cachexia." Journal of Clinical Oncology 7, no. 10 (1999): 3299-306.

Roubenoff, Ronenn. "The Pathophysiology of Wasting in the Elderly." The Journal of Nutrition 129, no. 1 (1999):256-9.

Tisdale, Michael J. "Wasting in cancer." The Journal of Nutri tion 129, no. 1 (1999): 243-6.

ORGANIZATIONS

National Center for Complementary and Alternative Medicine (NCCAM). 31 Center Dr., Room #5B-58, Bethesda, MD20892-2182. (800) NIH-NCAM, Fax (301) 495-4957.<http://nccam.nih.gov>.

The National Cancer Institute (NCI). Public Inquiries Office:Building 31, Room 10A31, 31 Center Dr., MSC 2580, Betheseda, MD 20892-2580 (301) 435-3848, (800) 4-CANCER, <http://cancer.gov/publications/>, <http://cancertrials.nci.nih.gov>, <http://cancernet.nci.nih.gov>.

American Institute for Cancer Research. 1759 R Street NW, Washington, D.C. 20009. (800) 843-8114 or (202) 328-7744. <http://www.aicr.org>, e-mail: support@aicr.org.

Crystal Heather Kaczkowski, MSc.

KEY TERMS

Anorexia

A condition frequently observed in cancer patients characterized by a loss of appetite or desire to eat.

Cachexia

A condition where the bodyweight "wastes" away, characterized by a constant loss of weight, muscle, and fat.

Cancer

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body.

Chemotherapy

Chemotherapy kills cancer cells using drugs taken orally or by needle in a vein or muscle. It is referred to as a systemic treatment due to fact that it travels through the bloodstream and kills cancer cells outside the small intestine.

Enteral nutrition

Feedings administered through a nose tube (or surgically placed tubes) for patients with eating difficulties.

Parenteral nutrition

Feeding administered most often by an infusion into a vein. It can be used if the gut is not functioning properly or due to other reasons that prevent normal or enteral feeding.

Protein-calorie malnutrition

A lack of protein and calories are consumed to sustain the body composition, resulting in weight loss and muscle wasting.

Radiation therapy

Also called radiotherapy; uses high-energy rays to kill cancer cells.

Wasting

When inadequate calories are consumed, it can lead to "wasting" or depletion of body mass. Wasting results in weight loss in tissues such as skeletal muscle and adipose tissue (fat).

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Weight Loss Diets

Weight Loss Diets

With over 50 percent of the population of the United States and other industrialized countries being either overweight or obese , a great number of people want to lose weight. However, weight loss is not easyand not often successful.

Weight gain is a result of consumed energy in the form of high-calorie foods eaten in excess of the body's need for energy. An adult's body needs energy to provide for its physiological functions, including heart, kidney, and liver function; blood circulation; respiration; muscle tone; and constant body temperature, called basal metabolic rate (BMR), as well as the energy spent in physical activity. An adult woman who is moderately active needs about 2,000 calories per day to meet all her nutrient requirements and maintain a healthy weight. She must therefore choose her diet carefully, avoiding fast foods and any other high-fat, high-sugar foods, eating a variety of fruits, vegetables, and whole-grain foods, and exercising regularly to avoid depositing excess body fat.

When energy consumption exceeds energy expenditure, excess energy is stored as fat in the body. A person usually gains weight gradually, adding less than a pound per month depending on the level of physical activity and amount and type of food eaten. It is very unusual to gain weight suddenly or at a faster rate than one pound per week. To be successful, the weight loss must also be gradual. Weight loss of one to two pounds per week is recommended, accompanied by a nutrient-dense diet with adequate amounts of high-fiber, whole-grain foods, and exercise.

In any weight loss attempt the goal is to lose the excess fat that has been accumulated in the body, rather than to lose weight. Therefore, strategies must be chosen carefully to achieve the goal of losing fat. Research has proven that the only long-term way to reduce body fat (and not body protein and water, which can be quick but ineffective) is to reduce the intake of high-fat and sugary foods and to exercise regularly. A successful weight loss diet must include adequate amounts of all essential nutrients that the body needs to maintain health. It is important to reduce the fat and concentrated carbohydrates (sugar, candy, high-fat and high-sugar desserts, fried foods, fatty meats, and whole-fat dairy products) in the diet, to reduce the intake of red meat and cheese as much as possible, and to avoid soft drinks (soda) and alcohol. However, if such a diet contains less than 1,600 calories per day, health will be compromised. It is also important to exercise regularly (at least thirty minutes per day, or more if the goal is to lose fat faster).

In spite of reports appearing in popular news magazines and newspapers on high-protein diets, scientific researchers in the field of nutrition believe that although high-protein diets may reduce food intake by inducing early satiety and increasing the thermic effect of foods temporarily, the long-term possibility of kidney problems, bone mineral loss, and other unknown long-term risk factors make these diets unsuitable for weight loss.

Losing weight at a rate of about one to two pounds per week is safe and doable. It takes a deficit of about 3,500 calories to lose a pound of weight, which can be accomplished in a week by cutting out 500 Kcalories per day. However, a young girl who eats 2,000 calories a day and cuts back to 1,500 calories per day may end up being deficient in iron and calcium . A better strategy would be to reduce calorie intake by 250 and burn the other 250 through exercise. That would equal about three miles of race walking or thirty minutes of bicycling each day. With this strategy, a very adequate, balanced, and normal diet can be followedone that provides all the necessary nutrients. Individuals can vary the foods they eat without getting tired of "being on a diet." Developing a regular exercise habit will not only aid weight loss but will help a person feel better.

Fad Diets and Weight Cycling

Many fad diets promise fast weight loss with little effort. However, any program that offers quick and easy results must be viewed with suspicion. If there were any way to easily lose weight there would not be so many over-weight and obese people around. Many people fall for these promises and start to lose weight (not fat), but they soon become tired or give themselves a vacation from dieting and gain the lost weight back, plus some more. Remembering their initial weight loss, they then go back on the diet and lose some of the gained weight, but not all of it. Repeating this cycle several times they end up gaining weight because each time they went off the diet they gained a little more weight than what they had lost.

This practice is called "weight cycling" or "yo-yo dieting." As an individual starts reducing his or her food energy intake, body cells sense the reduced energy and nutrients and start economizing in terms of energy expenditure in BMR. Therefore, less heat is produced by the body and less involuntary activity and physiological functioning are performed. As soon as the individual resumes his or her pre diet food habit, more fat is deposited in the body, resulting in a faster rate of weight gain. Repeating this cycle a few times results in a net weight gain rather than weight loss. Under these conditions the body composition also changes, and the percentage of body fat is increased. This increases the risk of degenerative diseases such as obesity , type II diabetes , cardiovascular disease, hypertension , and cancer .

In order to avoid these problems, an individual interested in losing weight should follow these recommendations:

  • Do not believe or follow any of the fad diets that promise easy and quick weight loss, because there is no such thing.
  • Combine weight reduction programs with exercise, which not only utilizes more energy, but also increases lean body tissue (muscle fibers), which in turn increases BMR.
  • Make sure that one's diet is varied, adequate in all essential nutrients, and includes adequate numbers of servings of fruits, vegetables, and whole-grain products.
  • Try to lose body fat rather than body weight by following an exercise program that includes resistance training as well as aerobic activity.
  • Be patient and lose weight gradually. Remember, weight gain did not happen fast, and neither will weight loss.
  • Avoid weight cycling.

see also Dieting; Fad Diets; Obesity; Yo-Yo Dieting.

Simin B. Vaghefi

Bibliography

Eisenstein, J.; Roberts, S.; Dallal, G.; and Saltzman, E. (2002). "High-Protein Weight-Loss Diets: Are They Safe and Do They Work? A Review of the Experimental and Epidemiological Data." Nutrition Review 60:189197.

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Weight Management

Weight Management

Obesity is a chronic condition, meaning it is unlikely to be cured, so behavioral interventions are needed to help people change their habits and improve their quality of life and their psychological functioning. The goal of weight management for obese people is to help them improve their unhealthful dietary and sedentary habits.

Weight-Management Strategies

Behavioral change interventions typically include a number of specific strategies, including self-monitoring, stimulus control, cognitive restructuring, stress management, social support, rewards, problem solving, physical activity, and relapse prevention. These interventions make it easier for people to stay on a healthful eating plan and a regular exercise program.

Self-monitoring.

The most important behavioral strategy for obese people to follow is self-monitoringthe observing and recording of behavioral patterns, followed by feedback on the behaviors. The obese person should keep a written notebook of all food that is ingested. This is best done on a regular basis, with entries written in a log as soon as possible after the food is eaten. Feedback means looking up and recording the number of calories that each food contained. In addition, it is also helpful to record the time of day that food is eaten, as well as one's mood, location, and other people present.

The number of minutes engaged in brisk walking or other physical activity should be recorded in the same notebook. In addition, a bathroom scale should be used to record one's weight on a daily basis. The primary goal of self-monitoring is to serve as a reminder of one's eating and exercise patterns. Results of such record keeping are clear: people who self-monitor lose more weight than those who do not. If a person uses only one weight-management strategy, it should be self-monitoring.

Stimulus control.

Stimulus control involves identifying the major barriers that are associated with unhealthful eating habits and sedentary patterns. Modifying these barriers by controlling environmental stimuli can help persons manage their weight-control behaviors. For example, one of the most common barriers to weight loss is a lack of time to exercise. Strategies to help persons find time during the day to exercise, such as setting their alarm clock to wake them up 45 minutes earlier and laying out exercise clothes and shoes before going to bed, are therefore important. When people get up earlier and exercise for even a few days, they tend to feel good about themselves and slowly develop the exercise habit. Other common stimulus-control strategies include avoiding high-risk places (such as a donut shop or fast-food restaurant), parking at the far end of the supermarket parking lot, and cleaning out the refrigerator and throwing out all high-calorie foods.

Cognitive restructuring.

Cognitive restructuring means changing the way people think about themselves. For example, some people think that they can lose a lot of weight quickly, such as thirty pounds in thirty days. Cognitive restructuring involves helping people set more realistic goals, such as losing about one pound a week and focusing on quality of life and improved health, not just cosmetic goals such as looking better.

Stress management.

Stress is one of the major predictors of abandoning a weight-loss or weight-control regimen. It triggers unhealthful eating patterns and is often associated with binge eating. Stress management involves teaching people to identify stressful situations and to learn to counteract the stress or tension. Strategies like brisk walking or jogging, meditating, or learning a relaxation response such as deep breathing can help reduce stress and provide distraction from the stress-producing situation.

Social support.

Good friends, family members, education classes, community programs, and other social activities can serve as good social-support networks. People with good support networks do better in weight management than people trying to make changes on their own. For example, walking with neighbors in the morning helps build relationships and may help people handle stressful situations in a better way.

Rewards.

Rewards for behavior change can help motivate people and reinforce healthful diets and exercise. Rewarding weight loss should be discouraged, however, because some people tend to use unhealthy strategies to achieve their goals. It is better to encourage specific behaviors, such as a certain number of minutes of exercise per day. Small rewards for small behavior changes make good sense for most people.

Problem solving.

Problem solving involves identifying and correcting high-risk situations involving one's eating and exercise habits. High-risk situations are usually emotional or social. For example, being invited to a new restaurant may make a person feel anxious. A problem-solving approach may involve calling the restaurant ahead of time and asking for healthful, calorie-controlled suggestions. Bringing a low-calorie vegetable plate to a party may make it easier to stay away from the high-calorie fried chicken wings. Problem solving means planning ahead for high-risk situations.

see also Appetite; Cravings; Eating Habits; Exercise; Fad Diets; Weight Loss Diets.

John P. Foreyt

Bibliography

Perri, Michael, and Foreyt, John P. (2003). "Preventing Weight Regain after Weight Loss." In Handbook of Obesity, edited by George Bray and Claude Bouchard. New York: Marcel Dekker.

Poston, Walker, S. C.; Hyder, M. L.; O'Bryne, K. K.; and Foreyt, John P. (2000). "Where Do Diets, Exercise, and Behavior Modification Fit in the Treatment of Obesity?" Endocrine 13:187192.

Wadden, Thomas A., and Stunkard, Albert J., eds. (2002). Handbook of Obesity Treatment. New York: Guildford Press.

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weight drop

weight drop A seismic-energy impulse produced when a heavy weight is allowed to fall and strike the ground. Weights vary from a few kilograms dropped from 2–3 m, for shallow seismic-reflection surveys, up to several tonnes dropped from 3–4 m, in large-scale, commercial, seismic-reflection surveys. In an accelerated weight drop, a mass (usually of no more than a few tens of kilograms) is accelerated towards the ground by compressed air, thus increasing the impact force and energy impulse. See also HAMMER; and SHOT.

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