Diet, Nutrition, and Weight Issues Among Children and Adolescents
Diet, Nutrition, and Weight Issues Among Children and Adolescents
One of the most disturbing observations about overweight and obesity in the United States is the epidemic of super-sized kids. A survey of adolescents in thirteen European countries, the United States, and Israel found that the United States, followed by Greece and Portugal, had the highest percentage of overweight teens (Inge Lissau et al., "Body Mass Index and Overweight in Adolescents in Thirteen European Countries, Israel, and the United States," Archives of Pediatrics and Adolescent Medicine, vol. 158, no. 1, January 2004). In 2006 more than twice as many American children and adolescents are seriously overweight than were overweight just twenty-five years ago. While there is no generally accepted definition for obesity as distinct from overweight in children and adolescents, the percentage of children who are overweight has quadrupled (from 4% to 16%) and the prevalence of overweight among adolescents has more than tripled (from 5% to 16%) since the 1960s. (See Figure 4.1.)
With children and teens as well as adults, body mass index (BMI; a formula describing the relationship between height and weight) is used to determine underweight, overweight, and at risk for overweight. Children's body fatness changes over the years as they grow, and girls and boys differ in their body fatness as they mature. In light of these differences, BMI for children (also referred to as BMI-for-age) is gender and age-specific. For example, Table 4.1 shows the BMI of a boy as he ages from two to thirteen years of age, with a typical decline in BMI during the preschool years and subsequent increases. Despite changing BMI with age, the boy in this example remains in the 95th percentile—at the cut-off point for overweight.
Overweight is defined as at or above the age- and gender-specific 95th percentile on the body mass index. Still, even children at the 85th percentile are considered at risk for overweight- and obesity-induced illness and overweight throughout their adult lives. Figure 4.2 shows BMI-for-age percentiles for boys aged two to twenty, and Figure 4.3 shows the comparable sex- and age-specific BMI percentiles for girls aged two to twenty.
Overweight children are much more likely to become overweight adults—an estimated 30% of adult obesity begins in childhood—unless they adopt and maintain healthier patterns of eating and exercise. The prevalence of overweight among adolescents is of particular concern because overweight adolescents are at even greater risk than overweight children of becoming overweight adults.
Like adults, children and adolescents are eating more than ever and exercising less. Although the link between obesity and disease in adolescence is weaker than it is for obese adults, teens who are overweight are at high risk of health problems later in life, and 50% to 80% of obese teens become obese adults. Type 2 diabetes, high blood lipid levels, and hypertension (high blood pressure) occur with increased frequency among overweight youth. Overweight children and teens are also at risk for psychosocial problems ranging from teasing and ostracism to social isolation and discrimination.
HOW MANY CHILDREN AND TEENS ARE OVERWEIGHT?
The most accurate data about the prevalence of overweight among children and adolescents come from the Centers for Disease Control and Prevention (CDC) National Health and Nutrition Examination Survey (NHANES) 1999–2002. The percent of overweight children (defined as BMI-for-age at or above the 95th percentile) continues to increase. Among children and teenagers ages six to nineteen, 16%-more than nine million are overweight according to the NHANES 1999–2002 data. This represents a 45% increase from the overweight estimates of 11% obtained from NHANES III (1988–94).
|BMI percentile for children and teens|
|source: BMI for Children and Teens, in BMI: Body Mass Index, Centers for Disease Control and Prevention, Division of Nutrition and Physical Activity, National Center for Chronic Disease Prevention and Health Promotion, April 2003, http://www.cdc.gov/nccdphp/dnpa/bmi/bmi-for-age.htm (accessed January 12, 2006)|
The 1999–2002 NHANES found that more than one-fifth of Mexican-American and non-Hispanic African-American children and teenagers were overweight. Mexican-American children ages six to eleven were more likely to be overweight (22%) than non-Hispanic black children (20%) and non-Hispanic white children (14%). Non-Hispanic African-American (21%) and Mexican-American adolescents (23%) ages twelve to nineteen were more likely to be overweight than non-Hispanic white adolescents (14%). In addition to the 16% of children and teens ages six to nineteen who were overweight in 1999–2002, another 15% were considered at risk of becoming overweight (a BMI-for-age between the 85th and 95th percentiles). The 1999–2002 NHANES findings of increasing percentages of overweight children and teens suggest the likelihood of yet another generation of overweight adults who may be at risk for subsequent overweight and obesity related health problems.
The prevalence of overweight children is highest among Mexican-origin boys (26.5%) and non-Hispanic African-American girls (22.8%). Nearly one-quarter of non-Hispanic African-American girls (23.6%) ages twelve to nineteen and Mexican-origin boys (24.7%) ages twelve to nineteen were overweight in 1999–2002. (See Table 4.2.)
The CDC also performs regular surveillance of the nutritional status of low-income children in federally funded maternal and child health programs. The Pediatric Nutrition Surveillance System (PedNSS) gathers and analyzes data about birth weight, short stature, underweight, overweight, anemia (iron deficiency), and breastfeeding. The state-specific data are used to identify common nutrition-related problems, identify high-risk groups, monitor trends, target resources for program planning, and evaluate the effectiveness of interventions—programs aimed at addressing nutritional deficiencies or problems. Table 4.3 shows the 2003 PedNSS state-specific prevalence data for these nutritional status indicators. Figure 4.4 shows how each of these indicators has improved since 1994 with the exception of the percent of children who are overweight.
|Overweight children and adolescents ages 6-19, by demographic characteristics, selected years 1963–65 through 1999–2002|
|[Data are based on physical examinations of a sample of the civilian noninstitutionalized population]|
|Sex, age, race and Hispanic orgina, and poverty status||1963–65 1966–70b||1971–74||1976–80 c||1988–94||1999–2002|
|Notes: — = Data not available. Overweight is defined as body mass index (BMI) at or above the sex- and age-specific 95th percentile BMI cutoff points from the 2000 Centers for Disease Control and Prevention growth charts. Age is at time of examination at mobile examination center. Crude rates, not age-adjusted rates, are shown.|
|aPersons of Mexican origin may be of any race. Starting with data year 1999 race-specific estimates are tabulated according to 1997 Standards for Federal Data on Race and Ethnicity and are not strictly comparable with estimates for earlier years. The two non-Hispanic race categories shown in the table conform to 1997 standards. The 1999–2002 race-specific estimates are for persons who reported only one racial group. Prior to data year 1999, data were tabulated according to 1977 standards. Estimates for single race categories prior to 1999 included persons who reported one race or, if they reported more than one race, identified one race as best representing their race.|
|bData for 1963–65 are for children 6-11 years of age; data for 1966–70 are for adolescents 12-17 years of age, not 12-19 years|
|cData for Mexicans are for 1982–84.|
|dIncludes persons of all races and Hispanic origins, not just those shown separately|
|eExcludes pregnant women starting with 1971–74. Pregnancy status not available for 1963–65 and 1966–70.|
|fPoverty status is based on family income and family size. Poor persons are defined as below the poverty threshold. Near poor persons have incomes of 100 percent to less than 200 percent of the poverty threshold. Nonpoor persons have incomes of 200 percent or greater than the poverty threshold. Persons with unknown poverty status are excluded.|
|gEstimates are considered unreliable.|
|source: "Table 74. Overweight Among Children and Adolescents 6-19 Years of Age, According to Sex, Age, Race, and Hispanic Origin, and Poverty Status: United States, Selected Years 1963–65 through 1999–2002, "in Health, United States, 2005, Centers for Disease Control and Prevention, National Center for Health Statistics, December 8, 2005, http://www.cdc.gov/nchs/data/hus/hus05.pdf#chartbookontrendsinthe (accessed January 9, 2006)|
|6-11 years of age||Percent of population|
|Not Hispanic or Latino:|
|Black or African American only||—||—||6.8||12.3||17.0|
|Not Hispanic or Latino:|
|Black or African American only||—||—||11.2||17.0||22.8|
|12-19 years of age|
|Not Hispanic or Latino:|
|Black or African American only||—||—||6.1||10.7||18.7|
|Not Hispanic or Latino:|
|Black or African American only||—||—||10.7||16.3||23.6|
The 2003 PedNSS considered records for more than five million children from birth to age five, from thirty-six states, the District of Columbia, Puerto Rico, American Samoa, and six tribal governments. In the 2003 PedNSS, 39% of records were from non-Hispanic white children, 33% from Hispanic children, 21% from non-Hispanic black children, 4% from Asian or Pacific Islander children, 1% from Native American or Alaska Native children, and 2% from children of all other or unspecified races and ethnicities.
PedNSS data revealed that the prevalence of underweight (low weight-for-length/BMI-for-age) in this population was just 5.2%, very close to the expected rate of 5%, but slightly higher than the 3.8% prevalence rate for U.S. children of the same ages. The overall prevalence of underweight decreased from 6.2% in 1994 to 5.2% in 2003. In contrast, the overall prevalence of overweight (high weight-for-length/BMI-for-age) in children aged two to five was 14.7%. The highest rates were among Hispanic children (19.4%) and Native American or Alaska Native (18%) and the lowest rates were among African-American (12%) and white (12.3%) children. (See Figure 4.5.) Overweight has increased among all racial and ethnic groups from 10.9% in 1994 to 14.7% in 2003. The relative increase in overweight was 35% from 1994 to 2003. In addition, the prevalence of at risk of overweight in children age two or older (in the 85th to 95th percentile BMI-for-age) increased from 13.9% in 1994 to 15.7% in 2003.
|State-specific prevalence of selected nutritional indicators of children aged 5 years, 2003|
|Contributor||Low birthweighta||High birthweighta||Ever breastfed||Breastfed 6 months||Anemiac||Short statured||Overweighte|
|aLow birthweight: <2,500 grams|
|bHigh birthweight: >4,000 grams.|
|cAnemia: Based on Centers for Disease Control and Prevention recommendations to prevent and control iron deficiency in the United States.|
Children aged 1 to 2 years: Hb < 11.0 g/dL or Hct < 32.9%; children aged 2 to 5 years: Hb < 11.1 g/dLor Hct < 33.0%. Altitude adjusted, children aged 6 months or older included in the analysis.
|dShort stature: Based on the 2000 Centers for Disease Control and Prevention growth reference, <5 percentile length-for-age for children younger than 2 years of age or height-for-age for children aged 2 years or older.|
|eOverweight: Based on the 2000 Centers for Disease Control and Prevention growth reference for children aged 2 years or older, BMI-for-age >95th percentile|
|fNational PedNSS = National Pediatric Nutrition Surveillance System.|
|source: B. Polhamus et al., "Table 1. State-Specific Prevalence of Selected Nutritional Indicators of Children Aged <5 Years, 2003 Pediatric Nutrition Surveillance System," in Pediatric Nutrition Surveillance 2003 Report, U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, 2004, http://www.cdc.gov/pednss/pdfs/PedNSS_2003_Summary.pdf (accessed January 12, 2006)|
|Cheyenne River Sioux (SD)||9.4||8.7||43.1||na||11.3||4.0||17.5|
|Chickasaw Nation (OK)||8.7||9.1||56.1||13.3||17.9||6.9||12.0|
|District of Columbia||11.9||5.8||48.5||26.4||21.0||7.2||13.3|
|Inter Tribal Council (AZ)||6.3||9.0||na||na||12.3||6.8||20.9|
|Navajo Nation (AZ)||6.7||7.0||75.2||32.9||8.3||5.3||14.4|
|Rosebud Sioux (SD)||7.4||9.5||57.2||29.3||17.8||3.2||17.3|
|Standing Rock Sioux (ND)||7.3||6.2||38.2||na||8.0||1.9||20.1|
WHY ARE SO MANY CHILDREN AND TEENS OVERWEIGHT?
Most children are overweight for the same reason as their adult counterparts—they consume more calories than they expend. Infants and toddlers appear to be effective regulators of caloric consumption, taking in only the calories needed for growth and development. By the time children are school age, this self-regulatory mechanism has weakened and when offered larger portions, they will eat them.
Heredity and environment play key roles in determining a child's risk of becoming overweight or obese. If one parent is obese, then there is a 50% chance that a child will be obese, and when both parents are obese, a child has an 80% chance of being obese. While there is mounting evidence of genetic predisposition and susceptibility to overweight and obesity, childhood obesity is still considered largely an environmental problem—the result of behaviors, attitudes, and preferences learned early in life. Children's relationships with food develop in response to family and cultural values and practices as well as the influences of school, peers, and the media.
The question remains—which environmental factors have given rise to the increasing prevalence of overweight children and teens during the past three decades? Many observers point to reliance on fat-laden convenience and fast foods along with time spent watching television, playing video games, and surfing the Internet instead of outdoor, physical activities. In 2003, 60% of female high school students and 73% of male high school students engaged in the recommended amount of moderate or vigorous physical activity. Figure 4.6 shows that the percentages of adolescents who obtained the recommended levels of physical activity decreased by grade throughout high school with just over half (51.6%) of twelfth-grade girls engaging in regular physical activity. Television viewing, media advertising, dwindling school physical education programs, neighborhoods where it is unsafe for children to play outdoors, and even working mothers have been implicated.
Working parents have been accused of a variety of nutritional and parenting infractions that have contributed to children's overindulgence in unhealthy foods. First, they leave children unsupervised and unable to satisfy their hunger with anything except cookies, chips, and soda. Some observers speculate that these children are starved emotionally—for time and atten-tion—as well as nutritionally. They also may be hungry for information, because while many adolescents are responsible for choosing and preparing their own food, they are often unprepared to make healthy choices.
Eating alone, in front of a television or computer, kids are more likely to overeat because they are lonely, bored, or susceptible to advertising cues. Overcome with guilt because they are not home to prepare meals, some working parents may intensify the problem by indulging their children with too many food treats. Stay-at-home parents do not necessarily convey healthier attitudes about food, eating, and nutrition than parents who work outside the home. Both groups may use food, especially sweets, to reward good behavior or may pressure children to clean their plates. Though these suppositions remain unproven, it is known that parents with eating disorders, obsessive dieters, and those with unhealthy eating habits are powerful, negative role models for children.
Children's Diets Receive Failing Grades
Most studies of children's nutrition reveal diets that are too high in fat, saturated fat, and sodium and too low in fiber. According to the U.S. Department of Agriculture (USDA), in 2001 just 16% of children met the recommended intake—10%—of saturated fat (Changes in Children's Diets: 1989–1991 to 1994–1996, January 2001). From 1989 to 1997, children's diets increased by about eighty to 230 calories per day, and most of these additional calories were derived from sugar-laden foods and beverages. Soft drink consumption rose by 40% between 1989 and 1996, from one to 1.4 servings per day. Depending on age and gender, from 56% to 85% of children drink soft drinks each day. Several studies have confirmed that children who drink soft drinks consume from fifty-five to 245 more calories per day than those who do not drink soft drinks. Worse still, soft drinks often replace healthy beverages such as low-fat milk or juice in children's diets. In 2001 just 30% of children had the recommended number of servings of milk per day—a 10% drop since 1989. Only 15% ate the recommended five or more servings of fruits and vegetables each day.
Between-meal snacking by teenagers also increased from 1.6 per day in 1977 to two per day in 1996 ("Taming Obesity: How Important Is the 'Snack Factor'?" http://nutrition.ucdavis.edu/perspectives/JanFeb02.htm). Snacking accounts for about 610 calories per day, up from 460 in 1977. Eating out at restaurants has also served to increase children's caloric consumption. In 1970 Americans spent about one-quarter of their food dollars on dining out. By 2001 the percent of food dollars devoted to dining out had nearly doubled, and children derived about one-third of their daily caloric intake from foods prepared outside the home—restaurant or take-out foods. One study, "Children's Patterns of Macronutrient Intake and Associations with Restaurant and Home Eating" (Journal of the American Dietetic Association, August 2001), found that when children ate meals at restaurants, they consumed nearly twice the calories they would consume at home. The study's authors, including Christine Zoumas-Morse, also reported that when children ate at restaurants they consumed more saturated fat than when they ate meals and snacks at home.
Results from the Youth Risk Behavior Surveillance
The Youth Risk Behavior Surveillance System is a national school-based survey conducted by CDC as well as state and local school-based surveys performed by education and health agencies. It examines health-risk behaviors among youth and young adults, including unhealthy dietary behaviors, physical inactivity, and overweight. This section summarizes key dietary findings from the national survey of students in grades nine through twelve conducted between February and December 2003.
|Percentage of high school who had eaten fruits and vegetables ≥5 times/day and who had drunk ≥3 glasses/day of milk, by sex, race/ethnicity, and grade, 2003|
|Category||Ate fruits and vegetables ≥5 timesa||Drank ≥3 glasses/day of milkb|
|aHad consumed 100% fruit juice, fruit, green salad, potatoes (excluding french fries, fried potatoes, or potato chips), carrots, or other vegetables ≥5 times/day during the 7 days preceding the survey.|
|bHad drunk ≥3 glasses/day of milk during the 7 days preceding the survey|
|source: Jo Anne Grunbaum et al., "Table 48. Percentage of High School Students Who Had Eaten Fruits and Vegetables ≥5 Times/Day and Who Had Drunk ≥3 Glasses/Day of Milk, by Sex, Race/Ethnicity, and Grade—United States, Youth Risk Behavior Survey, 2003," in "Youth Risk Behavior Surveillance—United States, 2003," in Morbidity and Mortality Weekly Report Surveillance Summaries, vol. 53, No. SS-2, Centers for Disease Control and Prevention, National Center for Health Statistics, May 21, 2004, http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5302a1.htm#tab48 (accessed September 27, 2005)|
Just one-fifth (22.0%) of students had eaten fruits and vegetables at least five times a day during the seven days preceding the survey. (See Table 4.4.) More male (23.6%) than female (20.3%) students reported having eaten fruits and vegetables five or more times per day. Overall, the prevalence of having eaten fruits and vegetables at least five times a day was higher among Hispanic (24.4%) than white (20.5%) students and higher among African-American male (26.1%) and Hispanic male (27.4%) than white male (21.2%) students. Similarly, the prevalence of having eaten fruits and vegetables at least five times a day was higher among younger students and decreased with age—ninth grade (23.3%), tenth grade (23%), eleventh grade (21.4%), and twelfth grade (19.5%).
Even fewer students (17.1%) had drunk at least three glasses of milk per day than had eaten the recommended servings of fruit and vegetables during the seven days preceding the survey. (See Table 4.4.) Overall, more white (20%) than African-American (11.6%) and Hispanic (13.1%) students had three or more glasses a day of milk during the seven days preceding the survey. The prevalence of having drunk at least three glasses of milk per day was higher among male (22.7%) than female (11.2%) students; higher among white male (26.8%), African-American male (16.0%), and Hispanic male (17.0%) than white female (12.8%), African-American female (7.5%), and Hispanic female (9.0%) students. Like fruit and vegetable consumption, the prevalence of drinking three or more glasses a day of milk was higher among younger students and decreased with age. Among male students, the rates were: ninth grade, 25.1%; tenth grade, 23.8%; eleventh grade, 22.6%; and twelfth grade, 18.1%. Among female students, the rates were even lower: ninth grade, 13.5%; tenth grade, 11.8%; eleventh grade, 9.8%; and twelfth grade, 8.9%.
Is Fast Food to Blame?
A staggering one-third of U.S. children eat fast food on any given day, consuming extra calories, sugar, and fat in the process. Shanthy A. Bowman and her colleagues looked at the diets of a representative sample of 6,212 children and teens. They found that boys, adolescents, and children who were African-American, of higher-income families, or from the South were most likely to eat fast food. However, children of all races, incomes, and U.S. regions commonly consumed fast-food meals. The researchers found that on a typical day, more than 30% of U.S. children ages four to nineteen ate burgers, fries, and other fast-food fare. In "Effects of Fast-Food Consumption on Energy Intake and Diet Quality among Children in a National Household Survey" (Pediatrics, vol. 113, no. 1, January 2004), the researchers found that children who ate fast food consumed an average of 187 more calories than did those who did not eat fast food, and, on average, children ate 126 extra calories on the days they ate fast food, compared with fast food-free days. In addition to consuming additional calories, children who ate fast food ingested more sugars, fats, and carbohydrates, while ingesting less fiber, fruits, vegetables, and milk than other children. The researchers calculated that the extra fast-food calories could result in an additional six pounds of weight gain in a year.
To determine how much soda and fast food California teenagers consume, researchers at the University of California, Los Angeles Center for Health Policy Research analyzed data from 4,000 twelve- to seventeen-year-old participants in the 2003 California Health Interview Survey. They found that more than two million California teens—about two-thirds of the total teen population in the state—drink soda every day and about 1.5 million eat fast food daily. The average California teen drinks 1.4 sodas per day, and consumption of soda and other sugary beverages increases with age. Seventeen-year-olds reported drinking 40% more soda (1.7 per day) than twelve-year-olds (1.2 per day). Teenage boys drink about 25% more soda and sweet drinks than do teenage girls, and African-American teens drink the most—averaging two sodas per day. Soda consumption declines with increasing household income. Teens with household income below 300% of the federal poverty limit drink more soda (1.5 to 1.6 per day) than teens from more affluent homes. Soda consumption was 25% higher among teens who said that sodas were available in school vending machines.
Nearly half (48%) of the state's teens eat fast food every day, and many eat fast food more than once a day. Almost 10%—more than 300,000 California teens—have fast food twice a day, and 90,000 eat fast food three or four times a day. As with soda consumption, more teens from low- and moderate-income homes eat fast food every day, and daily fast food consumption increases with age from 43.7% of twelve-year-olds to more than half (51.9%) of seventeen-year-olds. The researchers found that less than one-quarter of California teens eat the recommended five servings of fruit and vegetables each day. Not surprisingly, they also found a relationship between fast food consumption and eating the recommended servings of fruits and vegetables. The more often teens ate fast food the less likely they were to eat fruits and vegetables. Significantly more teens who said they did not eat fast food ate five or more servings of fruit and vegetables per day (Theresa A. Hastert et al., "More California Teens Consume Soda and Fast Food Each Day than Five Servings of Fruits and Vegetables," UCLA Health Policy Research Brief, September 2005).
Researchers at Children's Hospital in Boston think that proximity to fast food encourages children and teens to choose it. The researchers found that about 80% of U.S. teens attend schools within a ten-minute walk of one or more fast food vendors. The location of fast food outlets near schools throughout the nation may be intentional—enabling them to market directly to students as they commute to and from school, and at lunchtime. According to the CDC, about 20% of students do not even have to leave school to purchase fast food—Pizza Hut, Little Caesars pizza, Burger King, and McDonald's hamburgers are readily available in school cafeterias as are chips, candy, and sodas.
The Role of the Media
Despite recent television and print media anti-obesity campaigns, many industry observers condemn corporate marketing efforts and media for continuing to assault children with unhealthy messages that encourage them to eat junk foods. The CDC defines junk foods as those that provide calories primarily through fats or added sugars and have minimal amounts of vitamins and minerals. Michael F. Jacobson, executive director of the Center for Science in the Public Interest (CSPI), a nonprofit nutrition advocacy group based in Washington, D.C., believes that the United States has permitted junk-food marketers—not only fast-food companies, but also makers of sugary cereals and high-fat, high-calorie chips—to target children. In November 2003 he charged that the marketing of fatty, sugary, and low-nutrient foods had reached an all-time high and was fueling childhood obesity, and he called for restricting promotions targeted at the young.
Jacobson observed that even if parents lead by example in terms of healthy eating habits, it is still unfair to allow companies with slick, aggressive, sophisticated advertising campaigns to bypass parents, undermine parental authority, and directly influence children's food choices. Jacobson believes that parents must assume responsibility for ensuring that their children eat healthy meals and snacks; however, he says the marketers and media have an unfair advantage, "Companies are going directly to kids and saying, 'Eat this, eat this, drink this, drink this, it's yummy—you'll love it.' Parents have to say 'No, no, no,' and how many parents say no a thousand times?"
In an interview on a CBS news program ("Beware of Junk Food Marketers," The Early Show, CBSnews.com, November 11, 2003), Jacobson decried advertising of unhealthy foods on Saturday morning television and asserted, "Twenty-five years ago, the government tried to get junk food advertising off of children's television, but they were stopped by the toy industry, the food industry, the broadcasting industry and the advertising industry." CSPI has called upon the U.S. Department of Health and Human Services to work with Congress and the Federal Trade Commission to limit junk-food advertising aimed at children. Currently, federal rules do not restrict advertising content to children, only how much time ads can interrupt children's programming—10.5 minutes per hour on weekends and twelve minutes per hour during the week. Jacobson proposed that in view of the overwhelming evidence of the harmful effects of junk foods on American children's health, "It's time to take another crack at that." CSPI also advocates government-sponsored media campaigns that encourage healthy eating and physical activity.
In an interview in the December 10, 2003, issue of the Washington Post, Margo Wootan, a scientist at CSPI, contended that "This wouldn't be a problem if the marketing was promoting healthy foods. Children are exposed to an endless barrage of marketing everywhere they go throughout the day." Research conducted by CSPI found that marketing aimed at children, including marketing of food products, increased from $6.9 billion in 1992 to $15 billion in 2002. The CSPI report Pestering Parents: How Food Companies Market Obesity to Children (Washington, DC: Center for Science in the Public Interest, 2003) found that the spending power of children doubled each decade in the 1960s, 1970s, and 1980s and tripled during the 1990s. By the year 2000, children were spending a full one-third of their money to purchase foods and drinks. Wooten asserted that "Congress should give the Federal Trade Commission the authority and adequate funding to develop and implement (in consultation with the Department of Health and Human Services) nutrition standards for foods that can be advertised and marketed to children." She also criticized the use of fictional characters and real celebrities including classic children's favorites to promote unhealthy eating. Wooten lamented on the CSPI Web site, "SpongeBob Squarepants, Winnie the Pooh, Elmo, and even sports stars like Jason Giambi are enlisted to push low-nutrition foods on kids."
The CSPI report observed that the variety of ways that food companies market to children and teens extends beyond print and electronic media advertising to promotions in schools, in conjunction with manufacturers of books and toys, throughout the entertainment industry, and on the Internet. Examples of such promotions included:
- Pizza Hut rewards students who read a specified number of books with a coupon that entitles them to free Personal Pan Pizzas. CSPI observed that nutritionists advise parents not to use food to reward or punish children and that some states have prohibited the use of food to reward academic achievement.
- Food brand children's books, such as those published by the makers of M&Ms, Fruit Loops, Skittles, Her-shey Kisses, and Necco Sweetheart candies, often combine reading and eating. For example, the Oreo Cookie Counting Book involves eating ten cookies, which provide 535 calories.
- Web sites aimed at children and teens offer "adver-games" that blend product advertising into arcade game formats. For example, the Nabisco Web site boasts more than fifty games, puzzles, and contests sponsored by specific cookies and other snack foods. Preschoolers can search for Teddy Graham cookies, while older children play an adventure game in which finding Oreo cookie jars restores them to 100% good "health."
- Product placement, in which food manufacturers pay a fee or donate products for inclusion in movies and television programs, is another potent form of subliminal or stealth advertising—promotions that aim below the conscious perception of advertising. The CSPI report cited the appearance of the soft drink Dr. Pepper in the successful 2002 motion picture Spiderman, and McDonald's Big Mac, fries, and soda, along with the trademark golden arches in Spy Kids 2, another popular children's film released in 2002.
Some critics, including Velma LaPoint, professor of childhood development at Howard University in Washington, assert that advertisers exploit normal adolescent susceptibility to peer pressure with subliminal messages telling kids that they are "part of the in-crowd if you're consuming certain foods," and an outcast if you choose to forgo a particular soft drink or snack food (Katrina Woznicki, "Experts Debate Media's Role in Obesity," United Press International, December 10, 2003).
Educators and marketers observe that corporations remain eager to maintain a high-profile presence in schools, which enables them to remain highly visible to students. In 2005 McDonald's launched its "Passport to Play" program, which provides free lesson plans and materials to third- through fifth-grade physical education teachers. McDonald's describes the program, which has been distributed to 31,000 elementary schools nationwide, as reflecting the company's "commitment to balanced, active lifestyles today." Some critics object to commercialism of any kind in the schools, even if the message encourages healthy choices. Others believe that it is hypocritical for purveyors of low-nutrient foods to link these foods to physical fitness or athletic prowess.
The Media Can Deliver Powerful Nutrition and Health Education
During 2005 greater emphasis on children's diets inspired media efforts to offer nutrition education. Rather than subsisting on a diet of cookies alone, Sesame Street's Cookie Monster has begun championing healthy food choices. The beloved character is singing a new tune, "A Cookie Is a Sometimes Food." SpongeBob SquarePants, who in the past appeared on Breyer's ice cream cartons and Kellogg's sweetened cereals, has relocated to the produce section and is advocating fresh produce consumption. Along with SpongeBob Square-Pants, Dora the Explorer and other Nickelodeon characters appear on packages of fruit and vegetables, under licensing agreements with produce companies. Clifford the Big Red Dog promotes an organic cereal with his name and likeness and Arthur the aardvark has loaned his name and likeness to Arthur's Loops, another organic cereal.
Recent entries to children's television programming such as Jo Jo's Circus on Disney and Nickelodeon's Lazy Town aim to inspire young viewers to be physically active. Blending fitness and entertainment, video game makers have developed a genre of active rhythm games including Dance Dance Revolution, which features a workout mode that can track how many calories the user burns while playing. In the Groove and Pump It Up: Exceed are videogames in which players try to match the onscreen action by stepping on different sections of a floor pad, and Yourself!Fitness and Kinetic offer teens exercise routines in videogame formats.
Escape from Obeez City is an interactive DVD game that teaches children about the dangers of poor nutrition and inactivity, motivating them to change their behavior. Although Escape from Obeez City was developed by a company in Australia, the National Institutes of Health is funding videogame research projects in the United States as part of its anti-obesity efforts.
Although industry observers concede that the media can have a powerful and favorable effect on children's knowledge and awareness of healthy choices in terms of diet and exercise, many health professionals believe that television and video games alone will not solve the problems of childhood overweight, obesity, and inactivity. They assert that a concerted effort of families, schools, health professionals, food vendor, and the media is necessary to create the far-reaching cultural changes needed to modify children's diet and exercise habits. According to Tom Robinson, an associate professor of pediatrics at Stanford University ("Fat Is the Villain Here in 'Obeez City,'" Los Angeles Times, July 11, 2005), "If I had to choose between buying a child one of these active games or removing the TV from their bedroom and setting weekly TV time limits, I would strongly favor the latter."
Many Schools Offer Unhealthy Food Choices
Food manufacturers and marketers know that schools are ideal sites to promote their products to children and teens. Nearly all youth attend school and spend many of their waking hours at school. Further, the presence of foods in schools allows food companies to benefit from the implied endorsement of the schools and teachers. According to the CDC in Competitive Foods and Beverages Available for Purchase in Secondary Schools—Selected Sites, United States, 2004, nearly all high schools (98%), three-quarters of middle schools (74%), and 43% of elementary schools have vending machines, stores, or snack bars on campus that sell "competitive foods"—foods that are not part of federally reimbursable school meals. Figure 4.7 shows the types and sources of competitive foods in schools. The nutritional value of competitive foods is essentially unregulated, and students often purchase these foods instead of, or in addition to, school meals. In 2004 the majority (percentages ranged from 59.8% to 95% across states) of public secondary schools in twenty-seven states and eleven large urban school districts allowed the sale of less-nutritious competitive foods—snack food and beverages such as candy, soft drinks, salty snacks that are not low in fat, and cookies—from vending machines, snack bars, and cafeterias on the school campuses.
The CDC found considerable differences between the states and cities in the amount of junk food available in schools. Maine, Massachusetts, Connecticut, New Hampshire, and Texas had made the greatest strides in terms of reducing the amount of junk foods sold in their schools. In contrast, Oklahoma, Utah, and Washington offered the most non-nutritious foods and beverages. Table 4.5 shows that many more schools offer less-nutritious foods and beverages than healthier choices such as low-fat salty snacks and baked goods, fruit and vegetables. For example, 18.5% of Oklahoma schools offer fruits and vegetables, while 88.9% offer chocolate candy. In Connecticut 57.8% of schools offer fruits and vegetables, while 38.3% sell chocolate candy.
In addition to selling food in schools, food manufacturers advertise on vending machines, posters, book covers, scoreboards, and banners and offer schools educational materials, contests in which children receive prizes or food rewards for achievement, and fundraising opportunities. Some critics, including CSPI, assert that the manufacturers are taking unfair advantage of cash-strapped school districts. The National Association of State Boards of Education takes direct aim at these relationships between businesses and schools, decrying "cola wars" in which school districts bargained with franchises to obtain the highest-paying, exclusive marketing-rights contracts possible. In exchange for "pouring rights"—the exclusive right to sell and promote their products in the schools—the companies may pay the districts in excess of several million dollars. The National Association of State Boards of Education characterizes these relationships as "exploitation and a violation of the public trust."
A review prepared by Jim Bogden of the National Association of State Boards of Education, State Policies on the Sale of Food and Beverages at School, 2001 revealed that thirty-three states and territories simply administered USDA regulations governing school food programs that prohibit "foods of minimal nutritional value" from being sold in food service areas during meal times. The USDA definition of "foods of minimal nutritional value" (FMNV) does not include many popular high-fat snacks such as potato chips, tortilla chips, cheese puffs, and cookies. As a result, food sales are restricted only during meal times and non-nutritious food can, and often is, sold on school campuses in locations other than where meals are served. As of April 2005, twenty-eight states had policies that go further than the USDA regulations, which many nutritionists have derisively termed "policies of minimal nutritional value." (See Figure 4.8.) Some states extend the sales prohibition beyond meal times, and others forbid sales from the beginning of the school day until the end of the last lunch period. Maine had the most restrictive policy in 2005—banning all food sales that are not part of the school meals program and prohibiting use of vending machines on school campuses during school hours.
SCHOOLS SELL COMPETITIVE FOODS AND OBTAIN SUBSTANTIAL REVENUES FROM THEIR SALE
In 2004 a report from the U.S. Government Accountability Office (GAO) found that several states had enacted competitive food policies more stringent than those required by federal regulations. The policies and practices, however, varied widely. In 2005 the GAO analyzed data from two nationally representative surveys to determine the prevalence of competitive foods in schools, the groups involved in their sale, restrictions on competitive foods, and the amounts and use of revenue generated by their sale. In August 2005 the GAO issued its findings in School Meal Programs: Competitive Foods Are Widely Available and Generate Substantial Revenues for Schools.
The GAO analysis found that nearly all schools sold competitive foods during the 2003–04 school year, with middle schools and high schools more likely than elementary schools to offer competitive foods. Table 4.6 shows the percentages of elementary, middle, and high schools selling competitive foods via a la carte lines, vending machines, and school stores. In one-third of schools, sweet baked goods, salty snacks, and other less-nutritious foods were available in cafeteria snack lines. Schools often sold competitive foods at lunchtime, in the cafeteria or nearby, allowing kids to buy them for lunch or to supplement their lunches. Table 4.7 categorizes the types of competitive foods—nutritious, neither clearly nutritious nor less nutritious, and less nutritious—frequently available through all venues in elementary, middle and high schools.
|Percentage of public secondary schools allowing students to purchase foods and beverages and the percentage offering selected types of foods and beverages, by state or school district, 2004|
|State||Schools allowing Purchases from vending machines store, canteen, or snack bar (percent)|
|Less nutritious foods and beverages||More nutritious foods and beverages|
|Chocolate candy (percent)||Other kinds of candy (percent)||Salty snacks not low in fat (percent)||Soft drinks, sports drinks, or fruit drinks not 100% juice (percent)||Fruits or vegetables (percent)||Salty snacks low in fat (percent)||Low-fat baked goods (percent)||100% fruit juice (percent)||Bottled Water (percent)|
|*Survey did not include schools from one of the state's largest school districts.|
|source: L. Kann et al., "Table. Percentage of Public Secondary Schools Allowing Students to Purchase Foods and Beverages from Vending Machines or at the School Store, Canteen, or Snack Bar and, among Those Schools Allowing Purchases, the Percentage Offering Selected Types of Foods and Beverages, by State or School District—School Health Profiles, United States, 2004," in "Competitive Foods and Beverages Available for Purchase in Secondary Schools—Selected Sites, United States, 2004," in Morbidity and Mortality Weekly Report, vol. 54, no. 37, Centers for Disease Control and Prevention, National Center for Health Statistics, September 23, 2005, http://www.cdc.gov/mmwr/PDF/wk/mm5437.pdf (accessed January 12, 2006)|
|District of Columbia||62.4||33.4||47.9||52.4||84.7||16.0||52.4||28.5||78.3||89.2|
The analysis revealed that the during the period 1998–99 and 2003–04, the availability of competitive food venues in middle schools rose from 83% to 97%. During the same period, the number of middle schools with exclusive beverage contracts and the number of vending machines per school also increased. Three-quarters of high schools had exclusive soft drink contracts, and 65% of middle schools had exclusive beverage contracts in 2004, up from 26% five years before. Similarly, the volume and variety of competitive foods sold increased in more than two-thirds of high schools, more than half of middle schools and nearly one-third of elementary schools. School administrators attributed the increases to student demand, providing more nutritious and appealing food choices and generating additional revenues for the school food service.
Many different groups were involved in school food sales—students, parent-teacher associations, and booster groups as well as food services participated in competitive food sales. Generally, the number of groups involved and sales venues increased from elementary to middle school, with the most participants at the high school level. Figure 4.9 displays the groups and venues typically involved in competitive food sales in high schools.
In 2003–04, schools generated considerable revenues through competitive food sales, particularly middle schools and high schools. The top 29% of high schools, in terms of sales, generated in excess of $125,000 per school. (See Figure 4.10.) The analysts also found that all the school districts they examined had taken action to substitute healthy foods for less-nutritious competitive foods. The districts acknowledged that chief among obstacles to enacting these changes was concern about revenue losses.
Food for Thought Has New Meaning at Many Schools
As of September 2005 forty-two state legislatures had enacted or proposed measures that required or recommended nutritional guidance for schools. The 2004 reauthorization of the federal Child Nutrition Act requires every school district that receives federal funds to establish a local wellness policy by June 30, 2006, and USDA dietary guidelines released in January 2005 have prompted many schools' food services to offer more whole grains and fresh fruits and vegetables. Even before legislation mandates changes, many school districts have chosen to reconsider and replace some of the food and beverages available in their schools. For example, during 2004 Chicago area public schools replaced soft drinks sold in vending machines with water, juice, and sports drinks and replaced candy bars and fried chips with granola bars and baked chips. Vending machines in the Vista Unified School district in San Diego, California, formerly stocked with chips, candy, and sodas began offering granola bars, dried fruit, beef jerky, nuts, cut-up fruit, shaker salads, vegetables with ranch dressing, tuna packs with crackers, water bottles, milk, and fruit juice.
|Estimated percentage of schools of different levels with each competitive food venue, 2003–04|
|Elementary school||Middle school||High school|
|source: "Table 2. Estimated Percentage of Schools of Different Levels with Each Competitive Food Venue in 2003–2004," in School Meal Programs: Competitive Foods Are Widely Available and Generate Substantial Revenues for Schools, U.S. Government Accountability Office, August 2005, http://www.gao.gov/new.items/d05563.pdf (accessed January 12, 2006)|
|A la carte||67||88||91|
|One or more of the above venues||83||97||99|
|Type of competitive foods often or always available through any venue in schools, by school level and nutrition category|
|Elementary school||Middle schools||High schools|
|▴ Item is estimated to be available in approximately half or more schools with any venue|
|◯ Item is estimated to be available in approximately one-third or more schools with any venue|
|Note: The nutrition categories, as signified by the shading, are general descriptions of the foods in each category. Nutritional content can vary depending on the ingredients and the methods used to prepare foods.|
|source: "Table 4. Types of Competitive Foods Often or Always Available through Any Venue in Schools, by School Level and Nutrition Category," in School Meal Programs: Competitive Foods Are Widely Available and Generate Substantial Revenues for Schools, U.S. Government Accountability Office, August 2005, http://www.gao.gov/new.items/d05563.pdf (accessed January 12, 2006)|
|Milk, 1% or skim||▴||▴||▴|
|Milk, whole or 2%||▴||▴||▴|
|Vegetables and/or salad||▴||▴||▴|
|Less than 100% juice||◯||▴||▴|
|Low-fat salty snacks||▴||▴|
|Low-fat sweet baked goods||◯||▴|
|Low-fat frozen desserts||◯|
|Frozen desserts (not low-fat)||◯||▴|
|Salty snacks (not low-fat)||▴||▴|
|Sweet baked goods (not low-fat)||▴||▴|
Seattle's 100 public schools became "junk-food free" in 2004, and Arkansas took action to remove vending machines from elementary schools and require reporting of revenue from competitive food sales. In Buffalo, New York, schools are giving prizes to kids who eat lots of fruits and vegetables; and in schools in Sarasota, Florida, whole wheat bread and veggie pita sandwiches accompany several salad options.
Connecticut was the first state to pass a ban on selling sugar-sweetened sodas in schools. Similar bills have been introduced in seventeen other states. In July 2004 schools in Philadelphia, Pennsylvania, instituted a no-soda policy, and on September 15, 2005, California Governor Arnold Schwarzenegger signed legislation banning the sale of soda in state high schools.
New Jersey schools are adopting what may prove to be the most ambitious new statewide school nutrition policy in the nation. By 2007 all of the state's public schools must comply with a policy stipulating that soda, any food item listing sugar as its first ingredient, all forms of candy, and foods of minimal nutritional value (per the USDA definition) cannot be served, sold, or given for free anytime during the school day. Snacks and drinks sold anywhere on a school campus must have no more than 8 grams of fat and 2 grams of saturated fat per serving, and drinks cannot exceed more than 12 ounces, except bottled water. The policy applies to vending machines, cafeterias, a la carte items, school stores, school fundraisers, and the after-school snack program. The policy also makes nutrition education a requirement in school curricula.
Along with revamped food services, as of September 2005, five states—Arkansas, California, Florida, Missouri, and Pennsylvania have begun to collect BMI data during student growth screenings. In Pennsylvania, where 35% of children are overweight or at risk for overweight, BMI measurement will be required for students up to eighth grade in 2006, and for all students in the 2007–08 school year.
High School Physical Education Programs
School physical education programs, especially high school programs, have been found as lacking as school nutrition programs. In July 2005 a panel of national obesity experts convened by the CDC determined that children should get an hour of exercise over the course of each day. Yet CDC data reveal that participation in high school physical education classes declined by more than 10% between 1991 and 2003, and more than a third of high school students nationwide do not engage in vigorous physical activity ("Participation in High School Physical Education: United States, 1991–2003," Morbidity and Mortality Weekly Report, September 17, 2004).
The 2003 Youth Risk Behavior Surveillance System found that nationwide, 55.7% of students went to physical education (PE) classes on one or more days in an average week when they were in school. Enrollment in PE classes was higher among ninth graders (71%) and tenth graders (60.7%) than among students in eleventh grade (45.7%) or twelfth (39.5%). Among students enrolled in PE classes, a little more than three-quarters (80.3%) actually exercised or played sports for more than twenty minutes during an average PE class. (See Table 4.8.)
Less than one-third (28.4%) of high school students attended daily (PE) classes when they were in school. Daily PE attendance was higher among Hispanic (36.7%) than white (24.9%) students and higher among African-American male (37.1%) and Hispanic male (39.5%) than white male (26.8%) students. Daily PE class attendance declined in the upper grades of high school from 37.9% in ninth grade and 31.3% in tenth grade to 22.6% in eleventh grade and 18.2% in twelfth grade. (See Table 4.8.)
|Percentage of high school students who were enrolled in physical education (PE) class, attended PE class daily, and spent >20 minutes exercising or playing sports during an average PE class, by sex, race/ethnicity, and grade, 2003|
|Category||Enrolled in physical educatlon classa||Attended physical education class dallyb||Exerclsed or played sports >20 minutes during an average physical education classc|
|aOn one or more days in an average week when they were in school.|
|b5 days in an average week when they were in school.|
|cAmong the 55.7% of students enrolled in physical education class.|
|source: "Table 54. Percentage of High School Students Who Were Enrolled in Physical Education (PE) Class, Attended PE Class Daily, and Spent >20 Minutes Exercising or Playing Sports During an Average PE Class, by Sex, Race/Ethnicity, and Grade—United States, Youth Risk Behavior Survey, 2003," in "Youth Risk Behavior Surveillance—United States, 2003," in Morbidity and Mortality Weekly Report Surveillance Summaries, vol. 53, No. SS-2, Centers for Disease Control and Prevention, National Center for Health Statistics, May 21, 2004, http://www.cdc.gov/mmwr/PDF/SS/SS5302.pdf (accessed January 12, 2006)|
The importance of school PE programs cannot be underestimated, especially in view of the survey finding that one-third (33.4%) of students had not participated in sufficient physical activity during the seven days preceding the survey. The prevalence of insufficient physical activity was higher among females (40.1%) than male (26.9%) students. Overall the prevalence of participation in insufficient activity was higher among African-American (41.2%) and Hispanic (36.5%) than white (31%) students and higher among African-American females (50.4%) than white (37.5%) and Hispanic (42.6%) female students. (See Table 4.9.)
Just two-thirds (62.6%) of students had exercised vigorously for twenty or more minutes, three or more times per week in the seven days preceding the survey. More male (70%) than female (55%) students reported exercising vigorously, and the percentages of students who exercised declined with advancing grades. Almost three-quarters (73.1%) of ninth-grade males reported receiving sufficient vigorous physical exercise compared to only 46.4% of twelfth-grade female students. (See Table 4.10.)
GIRLS' INACTIVITY DURING ADOLESCENCE LEADS TO OBESITY
Decreasing physical activity during adolescence appears to play a major role in weight gain among girls as they grow from children to women. Investigators from several medical centers monitored and analyzed activity and BMI for 1,152 African-American and 1,135 white girls
|Percentage of high school students who participated in an insufficient amount of physical activity and no vigorous or moderate physical activity, by sex, race/ethnicity, and grade, 2003|
|Category||Participated in an insufficient amount of physical ativitya||No vigorous or moderate physical activityb|
|aHad not participated in sufficient vigorous physical activity and had not participated in sufficient moderate physical activity during the 7 days preceding the survey|
|bHad not participated in either vigorous physical activity or moderate physical activity during the 7 days preceding the survey.|
|source: "Table 52. Percentage of High School Students Who Participated in an Insufficient Amount of Physical Activity and No Vigorous or Moderate Physical Activity, by Sex, Race/Ethnicity, and Grade—United States, Youth Risk Behavior Survey, 2003," in "Youth Risk Behavior Surveillance—United States, 2003," in Morbidity and Mortality Weekly Report Surveillance Summaries, vol. 53, no. SS-2, Centers for Disease Control and Prevention, National Center for Health Statistics, May 21, 2004, http://www.cdc.gov/mmwr/PDF/SS/SS5302.pdf (accessed January 12, 2006)|
|Percentage of high school students who participated in sufficient vigorous physical activity and moderate physical activity, by sex, race/ethnicity, and grade, 2003|
|Category||Participated in sufficient vigorous physical activitya||Pariticipated in sufficient moderate physical activityb|
|aExercised or participated in physical activities that made students sweat and breathe hard for≥20 minutes on≥3 of the 7 days preceding the survey (e.g., basketball, soccer running, swimming laps, fast bicycling, fast dancing, or similar aerobic activities).|
|bPhysical activities that did not make students sweat and breathe hard for ≥30 minutes on ≥5 of the 7 days preceding the survey (e.g., fast walking, slow bicycling, skating pushing a lawn mower, or mopping floors).|
|source: "Table 50. Percentage of High School Students Who Participated in Sufficient Vigorous Physical Activity and Sufficient Moderate Physical Activity, by Sex, Race/Ethnicity, and Grade—United States, Youth Risk Behavior Survey, 2003," in "Youth Risk Behavior Surveillance—United States, 2003," in Morbidity and Mortality Weekly Review Surveillance Summaries, vol. 53, no. SS-2, Centers for Disease Control and Prevention, National Center for Health Statistics, May 21, 2004, http://www.cdc.gov/mmwr/PDF/SS/SS5302.pdf (accessed January 12, 2006)|
in San Francisco, Cincinnati, and Washington, D.C., as they grew from ages nine and ten years to eighteen and nineteen (Sue Y.S. Kim et al., "Relationship between Changes in Physical Activity and Body-Mass Index during Adolescence: A Multicentre Longitudinal Study, Lancet, vol. 366, July 23, 2005).
Inactive girls gained an average of ten to fifteen pounds more than girls who were active between the ages of nine and nineteen. The number of calories the subjects consumed increased slightly and did not appear to be associated with the weight gain. Though the investigators found only small differences in BMI between "active" girls and "inactive" girls at the age of nine and ten. (Active was defined as doing the equivalent of at least five brisk, thirty-minute walks each week, while inactive was doing no more than 2.5 thirty-minute walks weekly.) During the following nine years, however, inactive girls had triple the gains in BMI and were about ten to fifteen pounds heavier.
The investigators concluded that their findings "present a strong argument that physical inactivity in this age group is an important contributing factor to the development of obesity." They suggest actions to take to prevent the observed weight gain, such as encouraging teenage girls to add 2.5 hours of brisk walking each week to their schedules.
HEALTH RISKS AND CONSEQUENCES
The harmful health consequences of overweight and obesity can begin during childhood and adolescence. According to the CDC, more than half (nearly 60%) of overweight children have at least one cardiovascular risk factor compared to 10% of those with a BMI-for-age less than the 85th percentile, and 25% of overweight children have two or more risk factors. The most frequently occurring medical consequences of overweight among children and adolescents are:
- Elevated blood lipids—Overweight children and adolescents display the same elevated levels of cholesterol, triglycerides, and/or low-density lipoproteins as overweight adults. These hyperlipidemias are linked to increased risk for cardiovascular disease and premature mortality (death) in adulthood.
- Glucose intolerance and Type 2 Diabetes—Glucose intolerance, a carbohydrate intolerance that varies in severity, is a forerunner of diabetes. The incidence of Type 2 diabetes (also called non-insulin-dependent diabetes mellitus) among adolescents is increasing in response to the national rise in overweight among teens. A skin condition known as acanthosis nigricans—velvety thickening and darkening of skin fold areas at the neck, elbow, and behind the knee—often coexists with glucose intolerance in youth.
- Fatty liver disease—High concentrations of liver enzymes are associated with fatty degeneration of the liver (also termed hepatic steatosis) and have been found in overweight children and adolescents. Excessively high blood insulin levels (hyperinsulinemia) may contribute to the genesis of this disease.
- Gallstones—Although gallstones occur less frequently among children and adolescents who are overweight than in obese adults, nearly half of the cases of inflammation of the gallbladder (also called cholecystitis) in adolescents may be associated with overweight. Like adults, the risk for cholecystitis and gallstones in adolescents may decrease with weight reduction.
Another common health consequence of overweight is early maturation, a condition in which measurement of skeletal age is more than three months greater than chronological age. Early maturation is linked to overweight in adulthood and is also associated with the distribution of fat—it predicts the fat predominantly located on the abdomen and trunk that is in turn predictive of increased disease risk.
|Blood pressure levels for the 90th and 95th percentiles of blood pressure for boys ages 1 to 17 years|
|Age||BP percentile*||Systolic BP (mm Hg), by height Percentile from standard growth curves||Diastolic BP (mm Hg), by height percentile from standard growth curves|
|*Blood pressure percentile determined by a single measurement.|
|source: "Table 16. Blood Pressure Levels for the 90th and 95th Percentiles of Blood Pressure for Boys Ages 1 to 17 Years," in National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents, National Heart, Lung, and Blood Institute, http://www.cdc.gov/nccdphp/dnpa/growthcharts/training/modules/module3/text/hypertension_tables.htm (accessed January 12, 2006)|
Less frequently occurring health consequences include hypertension (high blood pressure), a condition that is nine times more frequent among children who are overweight compared with other children; obstructive sleep apnea (breathing becomes very shallow or stops completely because the windpipe becomes obstructed for short periods during sleep), a condition that afflicts an estimated 7% of overweight children; and orthopedic problems resulting from excessive stress on the feet, legs, and hips. Hypertension for children and adolescents one to seventeen years old is defined as average blood pressure readings at or above the 95th percentile (based on age, sex, and height) on at least three separate occasions. (See Table 4.11 and Table 4.12 for blood pressures by age and gender that are considered indicative of hypertension or at risk for hypertension. Children and adolescents between the 90th and 95th percentiles for their age, sex, and height are at risk for developing hypertension.) According to the CDC, several studies have confirmed that blood pressure and change in BMI during childhood were the two most powerful predictors of adult blood pressure across all ages and both genders (Overweight Children and Adolescents: Screen, Assess, and Manage, April 2005).
The results of a school-based survey of children and adolescents (ages nine, thirteen, and sixteen years) in Canada, presented at the 2003 American Heart Association's Annual Conference on Cardiovascular Disease Epidemiology and Prevention, suggested that increase in blood pressure is related to the obesity epidemic in children and adolescents. The McGill University School of Medicine investigators gathered information on lifestyle and demographic data as well as height, weight, blood pressure, and body fat, and calculated BMI for nearly 3,600 of the participants. They found that average blood pressure rose with increasing BMI categories in all age and sex groups (Joan Stephenson, "Obesity-Hypertension Link in Children?" Journal of the American Medical Association, vol. 289, no. 14, April 9, 2003).
|Blood pressure levels for the 90th and 95th percentiles of blood pressure for boys girls ages 1 to 17 years|
|Age||BP percentile*||Systolic BP (mm Hg), by height Percentile from standard growth curves||Diastolic BP (mm Hg), by height percentile from standard growth curves|
|*Blood pressure percentile determined by a single measurement.|
|source: "Table 17. Blood Pressure Levels for the 90th and 95th Percentiles of Blood Pressure for Girls Ages 1 to 17 Years," in National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents, National Heart, Lung, and Blood Institute, http://www.cdc.gov/nccdphp/dnpa/growthcharts/training/modules/module3/text/hypertension_tables.htm (accessed January 12, 2006)|
It has been demonstrated that severe obesity in teenagers damages the endothelium—the lining of the arteries—reducing their ability to expand. In 2005 investigators at St. George's Hospital Medical Center in London found that even modest overweight during adolescence compromises the arteries thereby increasing the risk of heart disease in adult life. Using ultrasound to examine the arteries of 471 teens aged thirteen to fifteen, researchers found that the arterial damage can occur at body mass index levels well below those considered to represent obesity. The investigators concluded that, "This emphasizes the importance of population-based strategies to control adiposity and its metabolic consequences in the young" (Peter H. Whincup et al., "Arterial Distensibility in Adolescents: The Influence of Adiposity, the Metabolic Syndrome, and Classic Risk Factors" Circulation, vol. 112, no. 12, September 20, 2005).
Very rarely, overweight children may suffer from increased skull pressure that causes severe headaches, dizziness, nausea, and vomiting (known as pseudotumor cerebri, because its symptoms mimic the symptoms caused by the pressure of a tumor), or a breathing disorder known as hypoventilation syndrome (also known as Pickwickian syndrome), in which excessive weight impedes movement of the chest wall and diaphragm necessary for breathing. As a result, breathing is shallow, and there may be decreased ability to oxygenate the blood.
The metabolic syndrome is a group of risk factors for atherosclerotic cardiovascular disease and Type 2 diabetes mellitus in adults that includes insulin resistance, obesity, hypertension, and hyperlipidemia. (Atherosclerosis is a hardening of the walls of the arteries caused by fatty deposits that build on the inner walls of the arteries and interfere with blood flow.) Atherosclerotic cardiovascular disease is the leading cause of death among adults, but occurs very rarely in young people. Recently, however, the risk factors—high blood pressure, elevated triglycerides (a fatty substance found in the blood), obesity, and low levels of the "good" HDL cholesterol—associated with its development have been appearing during childhood.
At the November 2003 meeting of the American Heart Association, researcher Joanne Harrell from the University of North Carolina at Chapel Hill, Center for Research on Chronic Illness, presented worrisome findings from a study of 3,200 boys and girls ages eight to seventeen years old showing a much higher prevalence of risk factors for metabolic syndrome than previous studies. More than half of the subjects had a least one of six risk factors—obesity, high blood pressure, high triglycerides, low levels of HDL cholesterol, glucose intolerance, and elevated insulin levels—for metabolic syndrome. The most common risk factor, found in more than 43% of the subjects, was a low HDL cholesterol level. More than 27% had two or more risk factors, and 13.5% had at least three risk factors. More girls (16.3%) than boys (10.7%) had at least three risk factors for metabolic syndrome. More than 8% of the children who had three or more factors were between eight and nine years old. The researchers hoped that the results of the study would serve as a warning that without effective intervention, many children and teenagers with these risk factors will develop Type 2 diabetes and heart disease.
In a review of recent research, "Diagnosis of the Metabolic Syndrome in Children" (Current Opinion in Lipidology, vol. 14, no. 6, December 2003), Julia Steinberger found that the process of atherosclerosis starts at an early age and is linked to obesity in childhood. Obesity beginning in childhood often precedes the hyper-insulinemia, and other components of the metabolic syndrome are also present in children and adolescents. Being overweight during childhood and adolescence is significantly associated with insulin resistance, dyslipidemia (high LDL and triglycerides, and low HDL), and high blood pressure in young adulthood. In view of the increasing prevalence of metabolic syndrome in children and adolescents, Steinberger recommended that "The first approach should focus on prevention of obesity in childhood. More attention should be paid to increasing physical activity and decreasing calorie consumption in this age group. Once obesity is established in a child or adolescent, vigorous clinical efforts should be directed at treating it."
In "Obesity and the Metabolic Syndrome in Children and Adolescents" (New England Journal of Medicine, vol. 350, no. 23, June 3, 2004), investigators asserted that the prevalence and magnitude of childhood obesity are increasing significantly and that the metabolic syndrome is far more common among children and adolescents than previously reported. They examined the effect of varying degrees of obesity on the prevalence of the metabolic syndrome in a large, multiethnic, multiracial cohort of children and adolescents and found that the prevalence of the metabolic syndrome increased with the severity of obesity and reached 50% in children and teens with severe obesity. The investigators also found that harbingers of an increased risk of cardiovascular disease, such as insulin resistance, C-reactive protein and interleukin-6 levels, rose with the degree of obesity, were already evident in these children and teens.
Mental Health Consequences
One of the most immediate, distressing, and widespread consequences of being overweight as described by children themselves is social discrimination and low self-esteem. Overweight and obese children and adolescents are at risk for such psychological and social adjustment problems as considering themselves less competent than normal-weight youth in social, athletic, and appearance arenas, as well as suffering from overall diminished self-worth. In "Health-Related Quality of Life of Severely Obese Children and Adolescents" (Journal of the American Medical Association, vol. 289, no. 14, April 2003), Jeffrey B. Schwimmer and his colleagues at the University of California, San Diego, found that obese children rated their quality of life with scores as low as those of young cancer patients undergoing chemotherapy (medical treatment to combat cancer). The researchers analyzed the responses of 106 children aged five to eighteen to a questionnaire used by pediatricians to evaluate quality-of-life issues. Study participants were asked to rate attributes such as their ability to walk more than one block, play sports, sleep well, get along with others, and keep up in school.
The results indicated that teasing at school, difficulties playing sports, fatigue, sleep apnea, and other obesity-linked problems severely affected obese children's well being. The obese subjects were five times more likely than healthy children and adolescents to have impaired physical functioning and 5.9 times more likely to suffer impaired psychosocial functioning. They were four times more likely than healthy children and adolescents to report impaired school function and had missed a mean of 4.2 days of school in the month prior to the study compared to less than one day of school missed for children who were not overweight. When the parents of the subjects completed the same questionnaires, their ratings of their children's abilities and well being were even lower than the children's self-reported ratings.
Researchers have found that obese children engage in more bullying behavior, at least in part because they deviate from appearance ideals. Obese boys were more than 1.5 times more likely to use their physical dominance to bully other children or to be victims of bullying than their normal-weight or overweight peers. Obese girls were more likely to be victims of bullying than their normal-weight peers (Lucy Jane Griffiths et al., "Obesity and Bullying: Different Effects for Boys and Girls," Archives of Disease in Childhood, vol. 96, 2006).
Another study, "Obesity, Shame, and Depression in School-Aged Children: A Population Study" (Rickard L. Sjoöberg et al., Pediatrics, vol. 116, no. 3, September 2005), found that depression is common among obese teenagers, and largely results from teens' experiences of being shamed. The investigators analyzed data from 4,703 teens aged fifteen and seventeen years and found that obese teens reported experiencing more symptoms of depression than their normal-weight or overweight peers and had a higher risk of depression. Obese teens were more likely than their normal-weight or overweight peers to say they had been treated in a degrading manner, had been ignored, or otherwise had shaming experiences within the past three months. Further, adolescents who reported the highest number of shame experiences were more than eleven times more likely to be depressed than those who reported the lowest number of shame experiences. The investigators concluded, "these results suggest that clinical treatment of obesity may sometimes not just be a matter of diet and exercise but also of dealing with issues of shame and social isolation."
Do Mental Health Problems Cause Overweight?
The mental health consequences of overweight and obesity—stigmatization, discrimination, isolation, and depression—are well known; however, recent research offers evidence that mental health and behavioral problems may be contributing to weight gain among children. In "Association between Clinically Meaningful Behavior Problems and Overweight in Children" (Pediatrics, vol. 112, November 2003), Julie C. Lumeng and her colleagues examined data about 755 children between the ages of eight and eleven derived from a national survey of children whose parents had answered questionnaires about their weight and behavior. After adjusting for a variety of risk factors associated with childhood obesity, the investigators concluded that behavioral problems were associated with a threefold increase in risk for overweight. This increase was comparable to other well-documented risk factors such as having a parent who was obese.
The type of behavior problems the children displayed did not appear to determine whether the children gained weight. Children who were aggressive or defiant were just as likely to become overweight as those who were withdrawn and showed other signs of depression. Although the research did not address the underlying reasons that behavioral problems are linked to weight gain, the investigators hypothesized that behavioral problems are often symptoms of depression and that "Kids who are depressed may be more likely to overeat and to sit around watching TV." They also suggested that future research will identify multiple relationships between obesity and depression, rather than simply cause and effect.
SCREENING AND ASSESSMENT OF OVERWEIGHT CHILDREN AND ADOLESCENTS
In view of the rising prevalence of overweight youth, screening children and adolescents for overweight and risk for overweight has assumed a prominent place in pediatric practice (the medical specialty devoted to diagnosis and treatment of children) and public health programs. The American Academy of Pediatrics Recommendations for Preventive Pediatric Health Care advise a frequent schedule of accurate weight and height measurements to determine whether children require further assessment or treatment for overweight. Figure 4.11 shows how screening for overweight distinguishes between youths who are not at risk of overweight, at risk of overweight, and overweight. Those deemed overweight receive an in-depth medical assessment; those considered at risk are assessed for changes in BMI, blood pressure, and cholesterol levels; and annual screening is advised for those who are not at risk of overweight.
The comprehensive assessment performed on overweight children and adolescents generally includes obtaining a detailed medical history to identify any underlying medical conditions that may contribute to overweight and analyzing family history for the presence of familial risks for overweight or obesity. Relevant
|Classification of cholesterol levels in high-risk children and adolescents*|
|Total cholesterol, ng/dL||L DL cholesterol, ng/dL|
|*i.e., children and adolescents from families with hypercholesterolemia or premature cardiovascular disease.|
|source: "Table 15. Classification of Cholesterol Levels in High-Risk Children and Adolescents," in Overweight Children and Adolescents: Screen, Assess, and Manage, Centers for Disease Control and Prevention, 2001, http://www.cdc.gov/nccdphp/dnpa/growthcharts/training/modules/module3/text/cholesterol.htm (accessed January 12, 2006)|
|High||greater than or equal to 200||greater than or equal to 130|
- familial factors include the occurrence of obesity, eating disorders, Type 2 diabetes, heart disease, high blood pressure, and abnormal lipid profiles such as high cholesterol among immediate family members. The assessment also may involve:
- Dietary evaluation to consider the quantity, quality, and timing of food consumed to identify foods and patterns of eating that may lead to excessive calorie intake. A food record or food diary may be used to assess eating habits.
- An evaluation of daily activities. This assessment involves an estimate of time devoted to exercise and activity as well as time spent on such sedentary behaviors as television, video games, and computer use.
- A physical examination to provide information about the extent of overweight and any complications of overweight, including high blood pressure. Children and adolescents with a BMI-for-age at or above the 95th percentile and who are athletic and muscular may be further assessed using triceps skinfold measurement to assess body fat. A measurement of greater than the 95th percentile indicates that the child has excess fat rather than increased lean body mass or a large frame.
- Laboratory tests, such as cholesterol screening, dictated by the degree of overweight, family history, and the results of the physical examination. Table 4.13 shows the range of values for total blood cholesterol and LDL cholesterol that are considered acceptable, borderline, and high.
- A mental health evaluation to determine the readiness of children and adolescents to change behaviors and to identify a history of eating disorders or depression that may require treatment. An assessment of the family's ability to support a child's weight-loss or weight-management efforts also may be performed.
INTERVENTION AND TREATMENT OF OVERWEIGHT AND OBESITY
In the absence of acute medical necessity, such as with children who are dangerously obese, most health professionals concur that drastic caloric restriction is an inappropriate weight-loss strategy for children who are still growing. Instead they advise efforts to stabilize body weight with a healthy, balanced diet, increased physical activity, and education about nutrition, food choices, and preparation. This approach is especially effective for children who are just slightly overweight, since maintaining body weight often allows them to "outgrow" overweight and become normal-weight adults.
When active weight loss is indicated, it is generally for children with BMI greater than the 95th percentile or those experiencing complications of overweight or obesity. Among children aged two to seven, gradual weight loss of about one pound per month is advised. Older children with serious health risks who are severely overweight (BMI greater than 35) may be advised to lose between one and two pounds per week. Figure 4.12 is a diagram displaying the criteria—age, BMI, and medical complications of overweight (hypertension, elevated lipids, sleep apnea)—health professionals use to determine whether weight maintenance or weight loss is recommended.
Many studies confirm that dietary interventions with children and teens are as ineffective long-term as they are with adults. In "Treatment of Pediatric and Adolescent Obesity" (Journal of the American Medical Association, vol. 289, no. 14, April 2003), National Institutes of Health investigators Jack and Susan Yanovski observed that studies found that long-term weight reductions were maintained in only about half of children and adolescents treated with intensive behavioral-modification therapy. Further, they characterized effective behavior-modification programs lacking widespread applicability because they are labor-intensive, not easily conducted by primary care physicians (pediatricians and family medicine physicians), and require intensive involvement from parents. Many practitioners believe that behavior modification alone is insufficient for severely obese children and adolescents. For this population, researchers and practitioners have had success with pharmacotherapy—drug treatment with medications known as "anorexiants," which reduce appetite by blocking the reuptake of the neurotransmitters norepinephrine and serotonin. The most serious adverse effects of these medications are increases in blood pressure and pulse rate sufficient to warrant reducing the drug dose or discontinuing it altogether. Like many other researchers and clinicians, the Yanovskis concluded that it "remains exceedingly difficult for overweight children and adolescents to lose weight, and even more difficult for them to sustain that weight loss long term. The ultimate goal must be prevention of the development of overweight in children and adolescents."
Robert Berkowitz and his colleagues at the Department of Psychiatry, Weight and Eating Disorders Program and the Children's Hospital, University of Pennsylvania School of Medicine, Philadelphia, compared the efficacy of family-based behavioral treatment alone to a combined regimen of family-based behavioral therapy and weight-loss medication among adolescents. The researchers reported the results of their study in "Behavior Therapy and Sibutramine for the Treatment of Adolescent Obesity: A Randomized Controlled Trial" (Journal of the American Medical Association, vol. 289, no. 14, April 9, 2003). For the first six months of the study, the eighty-two participants aged thirteen to seventeen with BMIs ranging from 32 to 44 received behavior therapy and sibutramine (an anorexiant medication marketed under the brand name Meridia) or behavior therapy and a placebo (an inactive compound). During the second six months all participants received behavioral treatment and sibutramine.
During the first phase, behavioral treatment called for participants to attend thirteen weekly group sessions followed up by six biweekly group sessions. In phase 2, the group sessions were conducted biweekly from months seven to nine and monthly from months ten to twelve. Parents met in separate group sessions held on the same schedule as the adolescents' meetings. Dietitians, psychologists, or psychiatrists conducted the groups. Participants in both treatment groups were instructed to consume a 1,200 to 1,500 calorie diet of conventional foods, with approximately 30% of their calories derived from fat, 15% from protein, and the remainder from carbohydrates. They were advised to incrementally increase their physical activity with the goal of walking or participating in aerobic activity for 120 minutes per week or more. Participants kept daily eating and activity logs that they submitted at each session.
At the end of the first six months, participants in the behavioral treatment and sibutramine group lost a mean of 7.8 kg (17.2 lbs) and had an 8.5% reduction in BMI, which was significantly more than weight loss of 3.2 kg (7.05 lbs) and reduction in BMI of 4% in the behavioral treatment and placebo group. Participants who received behavioral treatment and sibutramine also reported significantly less hunger. From months seven to twelve, participants initially treated with sibutramine maintained their weight loss with continued use of the medication, while those who switched from placebo to sibutramine lost an additional 1.3 kg (2.87 lbs). The researchers explained behavioral treatment and sibutramine participants' failure to lose further weight during the second phase of the study as consistent with the observation that weight loss tends to plateau in obese adults after six months of treatment with behavior therapy or pharmacotherapy.
The researchers concluded that weight-loss medications may be of benefit to adolescents. However, they cautioned that their use must be carefully monitored in adolescents, as in adults, to control increases in blood pressure and pulse rate. Absent the numerous large-scale studies necessary to confirm the safety and effectiveness of pharmacological treatment of obesity in adolescents, the researchers advised that "weight-loss medications should be used only on an experimental basis for adolescents."
Since adherence—sticking with any nutrition, diet, or exercise program—is an issue for adults and children, researchers Marsha Mackenzie and her colleagues reported about the successful implementation of a fun, family-centered nutrition and exercise program in "Effect of a Kids N Fitness© Weight Management Program on Obesity and Other Pediatric Health Factors" (Diabetes, vol. 49, supplement 1, May 2000). The weight-control program consisted of eight weekly, ninety-minute sessions with nutrition, education, and exercise components. Nutrition activities involved critical food label reading, dining-out strategies, supermarket shopping, snack preparation, and holiday eating tips. Each session also included a half-hour of exercise such as hip-hop dancing, aerobics, volleyball, or calisthenics. Families were educated to promote eating changes at home and to encourage attainment of individual exercise goals. The investigators reported decreasing weight gain per month and increasing exercise as well as significant positive changes in knowledge, physical function, children's health behaviors, children's physical and mental health, and self-esteem. They hypothesized that incorporating fun activities in a nonthreatening environment with peer and professional support was responsible for the favorable outcomes of the program.
Researchers agree that primary prevention is the strategy with the greatest potential for reversing the alarming rise in overweight and obesity among children and teens. Public health educators recommend counseling parents and caregivers about healthy eating habits for children. They advise offering children a variety of healthy foods, in reasonable quantities, to assist children to make wise food choices. Children should be encouraged, but not forced, to sample new foods and should not be pressured to clean their plates. No foods or food groups should be entirely off-limits, or children may become fixated on obtaining the forbidden foods.
Though it is difficult to impress children with the future health risks associated with excess weight, parents should be informed that obese children are more likely to suffer from diabetes, heart, and joint diseases such as osteoarthritis, as well as breast and colon cancer. Adults should model healthy habits, consuming no more that 30% of calories from fat, exercising regularly, and limiting time spent in front of the television. Health educators are especially eager to reduce children's television viewing, with its destructive blend of junk-food advertising and enforced inactivity. Finally, health professionals caution that food should not be used to punish or reward behavior nor as a way to comfort or console children. The undivided attention of a parent or caregiver or an expression of sympathy, reassurance, or encouragement may satisfy a child's need better than an ice cream cone or an order of French fries.
Researchers at Boston Medical Center found that parents are not always receptive to making lifestyle changes that could help their overweight children lose weight—particularly if the parents do not see their child's weight as a health issue. A study of 151 parents and found that 44% of parents of children who were overweight or obese did not see their child's weight as a problem and as a result, were not planning on instituting lifestyle changes in the near future. Another 17% of parents did recognize that their child had a problem and were considering making behavioral or lifestyle changes, but not soon. The researchers found that parents of children who were eight years old or older were more likely to be ready to address their child's weight issues than parents of younger children. The same was true of parents who believed their child's weight was a health issue; they were nearly ten times more likely than other parents to say they were ready to take actions such as increasing their childrens' fruit and vegetable consumption, limiting TV time, and encouraging exercise. Parents were also more open to change if they viewed themselves as overweight (Kyung E. Rhee et al., "Factors Associated With Parental Readiness to Make Changes for Overweight Children," Pediatrics, vol. 166, no.1, July 2005).
Overweight and obesity are among the most stigmatizing and least socially acceptable conditions in childhood and adolescence. Society, culture, and the media send children powerful messages about body weight and shape ideals. For girls these include the "thin ideal" and encouragement to diet and exercise. Messages to boys emphasize a muscular body and pressure to body build and even use potentially harmful dietary supplements and steroids. While gender has not been identified as a specific risk factor for obesity in children, the pressure placed on girls to be thin may put them at greater risk for developing eating-disordered behaviors. Although society presents boys with a wider range of acceptable body images, they also are at risk for developing disordered eating and body image disturbances. Several studies have reported that at age thirteen, girls' and boys' assessments of their bodies were comparable, but by age fifteen girls' body image had worsened significantly.
Adolescence is a developmental period marked by great physical change, and it is a time when many teens subject themselves to painful scrutiny. Uneven growth, puberty, and sexual maturation may make teens feel awkward and self-conscious about their bodies. Teenage girls are especially susceptible to developing negative body images—ignoring other qualities and focusing exclusively on appearance to measure their self-worth. This single-minded, and often distorted, destructive focus can result in lowered self-esteem and increased risk for mental health problems, including eating disorders.
Who Is at Risk?
Although there are biological, genetic, and familial factors that predispose to such eating disorders as anorexia nervosa (intense fear of becoming fat even when dangerously underweight) and bulimia (recurrent episodes of binge eating followed by purging to prevent weight gain) the emergence of these disorders is triggered by environmental factors. Chief among the environmental triggers is body image. Many researchers and health professionals believe that teenage girls who identify with the idealized body images projected throughout American culture are at increased risk for eating disorders.
Other risk factors are peer group pressures and such sociocultural forces as the fashion and entertainment industries and the media. The National Eating Disorders Association identifies media definitions of beauty, attractiveness, and health as among the myriad factors contributing to the rise of eating disorders. A landmark 1997 survey conducted by the Commonwealth Fund, In Their Own Words: Adolescent Girls Discuss Health and Health Care Issues, found that the media were their primary source of information about women's health issues. Another study found that in the course of twenty years three-quarters of articles about fitness or exercise plans in one teen adolescent magazine named "to become more attractive" as the reason to start exercising, and 51% cited the need to lose weight or burn calories.
Historically, the majority of adolescents with eating disorders have been first- or second-born white females from middle- to upper-class families. Girls who suffer from anorexia are often academically successful, with athletic prowess or training in dance. They tended to be perfectionists, well behaved, emotionally dependent, socially anxious, and intent on receiving approval from others. Adolescent girls with bulimia were generally more extroverted and socially involved. In the early twenty-first century the occurrence of eating disorders is increasing among younger children and throughout diverse ethnic and sociocultural groups. As many as 1% of adolescents have anorexia nervosa and between 2% and 3% suffer from bulimia.
According to the National Eating Disorders Association, surveys have found that preoccupation with thinness and dieting begins at an early age ("Statistics: Eating Disorders and Their Precursors," http://www.nationaleatingdisorders.org/). One study reported that 42% of first- to third-grade girls said they wanted to be thinner, and another found that 81% of ten-year-olds feared becoming fat. Between 30% and 40% of middle school girls are worried about their weight, and 40% to 60% of high school girls diet. A survey of female college students found that 91% had attempted to control their weight by dieting, and 22% said they were "often" or "always" dieting.
The 2003 Youth Risk Behavior Survey found that nationwide, 43.8% of high school students were trying to lose weight. The prevalence of trying to lose weight was higher among female (59.3%) than male (29.1%) students and higher among white females (62.6%) than African-American female students (46.7%). During the thirty days preceding the survey, 42.2% of students said they had eaten less food, fewer calories, or low-fat foods to lose weight. Table 4.14 shows the percentage of students who used healthy behaviors such as modifying their diets or exercising to control their weight.
Nationwide, 13.3% of students had gone without eating for twenty-four hours or more in an effort to lose weight during the thirty days, 9.2% had taken diet pills, powders, or liquids without a physician's advice, and 6% had vomited or taken laxatives to lose weight or keep from gaining weight. More female (8.4%) than male (3.7%) students had used this latter strategy, and the prevalence of vomiting or laxative use was higher among white (8.5%) and Hispanic female (9.7%) than African-American female (5.6%) students. Table 4.15 shows the percentage of high school students who engaged in these unhealthy practices in an effort to lose weight or toprevent weight gain.
|Percentage of high school students who engaged in healthy behaviors associated with weight controla to lose or to keep from gaining weight, by sex, race/ethnicity, and grade, 2003|
|Category||Ate less food, fewer calories, or foods low in fat to lose weight or to keep from gaining weight||Exercised to lose weight or to keep from gaining weight|
|aDuring the 30 days preceding the survey.|
|source: "Table 62. Percentage of High School Students Who Engaged in Healthy Behaviors Associated with Weight Control to Lose Weight or to Keep from Gaining Weight, by Sex, Race/Ethnicity, and Grade—United States, Youth Risk Behavior Survey, 2003," in "Youth Risk Behavior Surveillance—United States, 2003," in Morbidity and Mortality Weekly Report Surveillance Summaries, vol.53, no. SS-2, Centers for Disease Control and Prevention, National Center for Health Statistics, May 21, 2004, http://www.cdc.gov/mmwr/PDF/SS/SS5302.pdf (accessed January 12, 2006)|
Which Variables Are Associated with Dieting, Overweight, and Eating Disorders?
Dianne Neumark-Sztainer and Peter J. Hannan, researchers at the University of Minnesota, Minneapolis, analyzed a representative sample of 6,728 adolescents in grades five through twelve who completed the Commonwealth Fund surveys about the health of adolescent girls and boys. The objectives and results of the research were detailed in "Weight-Related Behaviors among Adolescent Girls and Boys: Results from a National Survey" (Archives of Pediatrics & Adolescent Medicine, vol. 154, no. 6, June 2000). The research aimed to assess the prevalence of dieting and disordered eating among adolescents; the sociodemographic, psychosocial, and behavioral variables that were associated with dieting and disordered eating; and whether adolescents report having discussed weight-related issues with their health-care providers. (The researchers defined disordered eating as weight-related behaviors such as anorexia and bulimia nervosa, self-induced vomiting, binge eating, inappropriate or extreme dieting, and obesity.)
Subjects were assessed by calculating BMI and eliciting weight-related attitudes and behaviors. For example, dieting was assessed by asking such questions as "Have you ever been on a diet?" and "Why were you dieting?" Behaviors were assessed by posing a question such as "Have you ever binged and purged (which is when you eat a lot of food and then make yourself throw up, vomit, or take something that makes you have diarrhea) or not?" Subjects also were asked "Right now, how would you describe yourself?" to gain an understanding of their perceptions of their weight. Psychosocial and behavioral variables including self-esteem, stress, depression, substance use (of tobacco, alcohol, or illegal drugs), and level of physical activity were also measured and scored using standardized questionnaires and inventories.
|Percentage of high school students who engaged in unhealthy behaviors associated with weight controla, by sex, race/ethnicity, and grade, 2003|
|Category||Went without eating for >24 hours to lose welght or to keep from gaining welght||Took diet pills, powders, or liquids to lose welght or to keep from gaining welghtb||Vomited or took laxatives to lose weight or to keep from gaining welght|
|aDuring the 30 days preceding the survey.|
|bWithoukt a doctor's advice.|
|source: "Table 64. Percentage of High School Students Who Engaged in Unhealthy Behaviors Associated with Weight Control, by Sex, Race/Ethnicity, and Grade—United States, Youth Risk Behavior Survey, 2003," in "Youth Risk Behavior Surveillance—United States, 2003," in Morbidity and Mortality Weekly Report Surveillance Summaries, vol. 53, no. SS-2, Centers for Disease Control and Prevention, National Center for Health Statistics, May 21, 2004, http://www.cdc.gov/mmwr/PDF/SS/SS5302.pdf (accessed January 12, 2006)|
The study revealed that 24% of the population was overweight, with nearly half of the girls and 20%of the boys reporting a history of dieting. Twenty percent of the population reported disordered eating (13% of girls and 7% of boys), which was associated with a range of behavioral variables including overweight, low self-esteem, depression, suicidal ideation (thoughts, intent, or plans to take one's own life), and substance use. Nearly half of the adolescents recalled discussions about nutrition with a health-care provider, but just 24% of girls and 15% of boys said they had discussed eating disorders with a health-care provider.
Younger girls (grades five through eight) were significantly less likely to engage in dieting and disordered eating than older girls (grades nine through twelve), and dieting was reported by 31.1% of the fifth-grade girls and increased to 62.1% among twelfth-grade girls. The prevalence of disordered eating was highest among Hispanic girls and lowest among non-Hispanic African-American girls, and the prevalence of dieting was highest among white non-Hispanic girls and lowest among non-Hispanic African-American girls. The researchers observed that the prevalence rates of dieting behaviors were lowest among African-American girls, suggesting that black girls may experience lower levels of body dissatisfaction than white girls.
Alcohol and drug use were directly associated with dieting and disordered eating among girls and boys; however, the association between substance use and disordered eating was stronger than the association between substance use and dieting. Tobacco use was associated with dieting and disordered eating among girls, but not among boys.
The researchers were heartened to discover that "about half of the youth reported that a health-care provider had discussed nutrition and weight issues with them," and observed that while the content of such discussions was unclear, "at least the youth remembered that the issues had been discussed." They concluded that "the high rates of dieting and disordered eating behaviors, coupled with the high prevalence of obesity found in this and previous studies indicate a clear need for interventions aimed at the primary and secondary prevention of weight-related disorders. The large scope of the problem and the complexity of the issues at hand indicatethat there is a need for multiple interventions at the individual and familial level (e.g., within clinical practices), at the group level (e.g., within school settings), and at the community or larger societal level (e.g., changes in the physical and social environment)."