Adolescent Health Care: A Practical Guide

Chapter 32

Obesity

Marcie B. Schneider

Obesity is a serious medical problem that is increasing in prevalence in the adolescent and adult population. Almost two thirds (65.7%) of adults are overweight or obese. Obesity is associated with up to 325,000 deaths/year and a shortened lifespan.

Obesity is a now a common problem among adolescents. In children and adolescents, the term obesity has been replaced by overweight. The prevalence of overweight in American adolescents ranges from 12.7% to 24.7%, depending on gender and race. It is a condition in which the psychobiological cues for eating are discordant with energy requirements. Both genetic and environmental factors contribute to overweight problems. Studies on fraternal twins raised apart suggest a strong genetic influence on body mass index (BMI). Genetic mutations have also been identified. Endocrine and metabolic causes such as hypothyroidism, hypercortisolism, and Prader-Willi syndrome occur infrequently in adolescents.

The Expert Committee on Clinical Guidelines for Overweight in Adolescent Preventive Services (Himes and Dietz, 1994) recommends screening adolescents for overweight and at risk for overweight by using the BMI. The BMI is equal to the weight in kilograms divided by the square of the height in meters:

Adolescents' body fatness changes over the years with growth and development. Teenage girls and boys differ in their body fatness as they mature. This is why BMI for adolescents, also referred to as BMI-for-age, is gender and age specific. It is an easy index to calculate and has a correlation of 0.7 to 0.8 with body fat content in adults. The correlation coefficient of BMI with body fat content is 0.39 to 0.90 in children and adolescents.

For children and adolescents, at risk for overweight is defined as a BMI between the 85th and 95th percentiles for age and gender, while overweight is defined as BMI exceeding the 95th percentile for age and gender. BMI values in adolescents are listed in Chapter 1 (Figs. 1.25 and 1.26). Chapter 4 (Figs. 4.8 and 4.9) also shows height, weight, and BMI by age and gender. BMI-for-age charts can be obtained from the Centers for Disease Control and Prevention (CDC) on their Web site: www.cdc.gov/growthcharts/.

The standards for defining obesity in adults 20 years and older were changed in 1998, following changes to the World Health Organization (WHO) definitions in 1995. This has increased the number of adults identified in the United States as being overweight or obese. The definition changed the lower limit for BMI for overweight persons from 27.8 kg/m2 in adult men and 27.3 kg/m2 in women to 25 kg/m2.

The criteria published in 1998 by the National Heart, Lung and Blood Institute (NHLBI) of the National Institutes of Health (NIH) (1998) in Clinical Guidelines for Identification, Evaluation, and Treatment of Overweight and Obesity in Adults (Archives of Internal Medicine, 1998) include the following:

NHLBI Classification

BMI Range (kg/m2)

Underweight

<18.5

Normal

18.5–24.9

Overweight

25–29.9

Obesity class I

30–34.9

Obesity class II

35–39.9

Extreme obesity class III

≥40

Although total body fat can be measured indirectly by a variety of techniques, its use is limited to the research laboratory or clinical studies. However, a clinically useful method is the measurement of triceps skinfold thickness. Barlow and Dietz (1998) published a chart of triceps skinfold thickness for age and gender where greater than the 95th percentile suggests excessive fatness (Table 32.1).

To measure triceps skinfold, calipers are placed 1 centimeter above the midpoint between the acromion and olecranon process on the posterior (triceps area) of a relaxed right arm and measured 3 times, using the average as the thickness. This measurement does not take into account the regional distribution of body fat, which in adults has been correlated with future obesity-related health risk. Potentially useful measurements in adults older than 20 years are the waist circumference and the waist-hip ratio. Many studies have demonstrated distribution of body fat as an independent risk factor for cardiovascular disease. Visceral abdominal fat is more likely to contribute to elevated blood cholesterol and other lipid abnormalities, glucose intolerance, and hypertension. Normal values for waist circumference in children and adolescents are being studied. A recent study using these norms correlated waist circumference with risk for insulin resistance (Hirschler et al., 2005).

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TABLE 32.1
Triceps Skinfold Measurements in Children and Adolescents

Age in Years

95% Skinfold Thickness in Males (mm)

95% Skinfold Thickness in Females (mm)

Adapted from Barlow SE, Dietz WH. Obesity evaluation and treatment: expert committee recommendations. Pediatrics1998;102:e29.

6–6.9

14.6

16

7–7.9

16.7

18

8–8.9

17

20

9–9.9

19.9

22

10–10.9

21

24

11–11.9

22

26

12–12.9

23

28

13–13.9

24

30

14–14.9

23

31

15–15.9

22

32

16–16.9

22

33

17–17.9

22

34

18–18.9

22

34

19–19.9

22

35

In summary, methods that use just height and weight are inexpensive and easy to use but do not reflect regional body fat distribution. Skinfold measurements can be inaccurate due to interobserver error. Further research on waist circumference in children and adolescents may prove to be a useful measure. The current developmentally based BMI percentile curves overcome many of the difficulties found in the past height-for-weight charts, but still do not reflect important body fat distribution characteristics.

Pubertal Changes

Effects of Puberty on Body Composition

During adolescence, lean body mass increases in both sexes. The increase is greater in males because of their greater increase in skeletal muscle. The maximum increase in muscle mass occurs at about the time of peak height velocity (PHV) in both sexes, whereas the maximum fat deposition occurs 2 years before PHV. However, in females, fat deposition continues throughout puberty and females ultimately have more body fat than males.

Effects of Obesity on Puberty

  1. Overweight adolescents tend to be taller and larger in skeletal mass and more advanced in skeletal development. Shortness in an overweight preadolescent or early adolescent should raise a “red flag” for possible endocrine disease.
  2. Overweight female adolescents tend to have earlier sexual maturation. Black females however, have earlier menarche than whites even after adjustment for weight and height. A recent study (Sun et al., 2005) demonstrated that over that past 30 years menarche has occurred 0.46 and 0.25 years earlier in black and white girls respectively; the current median age of menarche in black girls is 12.06 years and in white girls is 12.55 years.
  3. Menstrual irregularities are often seen in overweight adolescents. Aromatization of androgens to estrogen occurs in adipose tissue and is a significant source of extragonadal estrogen. Therefore, excessive body fat, through its effect on peripheral estrogen metabolism, may lead to suppression of follicle-stimulating hormone (FSH) and sensitization of the pituitary gland to release gonadotropin-releasing hormone, with a resultant increase in luteinizing hormone (LH). The resultant changes in FSH and LH can stimulate androstenedione and testosterone production in the ovary and can be associated with the anovulatory cycles characteristic of polycystic ovarian syndrome.

Etiology

Many theories have been advanced, but the cause of obesity is still unclear. Obesity is a chronic condition with multiple factors contributing to its etiology. Genetic, cultural, socioeconomic, behavioral, and situational factors all play a role in establishing dietary habits and thereby weight control. At some time in future, obesity may be divided into different disease classifications, with therapies tailored to match the underlying cause. At present, only 5% of overweight children and adolescents have an underlying cause identified. This includes approximately 3% with endocrine problems (hypothyroidism, Cushing syndrome, hypogonadism) and 2% with rare syndromes (Prader-Willi, Laurence-Moon-Biedl, Fröhlich, Alström, Kallmann).

Influencing Factors

Familial or Genetic

  1. There is an increased incidence of obesity among those with obese parents. In one study of Swedish twins, if one parent was obese, there was a 30% risk for the child to be overweight; if both parents were obese, there was a 70% risk for the child to be overweight. Despite the genetic implications, these findings may also be partially environmentally influenced.
  2. Stunkard et al. (1990) found a high correlation of BMI between twins, even when reared apart.
  3. Stunkard et al. (1986) also demonstrated that there was a strong relationship between the weight class of adoptees and the BMI of their biological parents. There was no relationship between the weight class of the adoptees and the BMI of their adoptive parents.
  4. Identified genes linked to obesity include mutations in leptin, leptin receptor, neuropeptide Y, proopiomelanocortin, prohormone convertase 1, and melanocortin receptor MC4R. Obesity loci have been found on chromosomes 2, 5, 10, 11, and 20.

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Activity and Energy Expenditure

There are conflicting reports regarding energy expenditure in obese individuals. Obese individuals filmed in time-lapse photography seem to move less than normal-weight individuals. Although some studies show no evidence to implicate a decrease in energy utilization in those who are overweight, Ravussin et al. (1988) found that the rates of energy expenditure were lower in obese individuals and that these rates of expenditure seem to cluster in families. Dietz (1993), drawing from longitudinal data collected in the National Health and Nutrition Examination Surveys (NHANES) study, stated that the most powerful predictor of the development of overweight in adolescence was the time that a child (6–11 years) spends viewing television, even after controlling for other known variables associated with overweight in childhood. For every extra hour of television watched by 12- to 17-year olds, there is a 2% increase in prevalence of overweight. Hernandez et al. (1999) found a 12% increase in prevalence of overweight for each hour of television watched and a 10% decrease in overweight prevalence with every hour of daily exercise in Mexican children. Recently, Epstein et al. (2005) reported that decreasing sedentary behaviors led to a decrease in energy intake, and Gutin et al. (2005) found that adolescents who regularly engaged in exercise were more likely to be fit and lean.

Caloric Intake

Caloric intake is variably elevated in overweight adolescents and is dependent on where they eat. In one study, overweight adolescent boys ingested more calories at school than at home, compared with their lean counterparts. Retrospective diet histories tend to underreport caloric intake in both overweight and nonoverweight adolescents, but more so in the overweight.

Behavior

Overweight adolescents often exhibit the following behaviors:

  1. Eating fast
  2. Skipping breakfast and lunch and ingesting most of their food at night
  3. Eating not when hungrybut when food is available or when their appetite is stimulated by environmental cues
  4. Eating when depressed or anxious
  5. Eating in association with other activities, such as watching television
  6. Underestimating the total number of calories ingested
  7. Overindulging in “fast foods”
  8. Participation in unhealthy weight control practices
  9. Increased sedentary behavior

TABLE 32.2
Prevalence of at Risk for Overweight and Overweight in Children by Sex, Age and Racial/Ethnic Group NHANES 1999–2002

Sex

Age, yr

All BMI >85%

Non-Hispanic White BMI >85%

Non-Hispanic Black BMI >85%

Mexican-American BMI >85%

All BMI >95%

Non-Hispanic White BMI >95%

Non-Hispanic Black BMI >95%

Mexican-American BMI >95%

From Hedley AA, Ogden CL, Johnson CL, et al. Prevalence of overweight and obesity among US children, adolescents and adults, 1999–2002. JAMA 2004;291:2847.

Boys and girls

6–11

31.2

28.6

33.7

38.9

15.8

13.5

19.8

21.8

Boys and girls

12–19

30.9

27.9

36.8

40.7

16.1

13.7

21.1

22.5

Boys

6–11

32.5

29.3

29.7

43.9

16.9

14.0

17.0

26.5

Boys

12–19

31.2

29.2

32.1

41.9

16.7

14.6

18.7

24.7

Girls

6–11

29.9

27.7

37.9

33.8

14.7

13.1

22.8

17.1

Girls

12–19

30.5

26.5

41.9

39.3

15.4

12.7

23.6

19.9

Epidemiology

  1. Data from the NHANES from 1999 to 2002 showed that a substantial proportion of children and adolescents in the United States were overweight (Table 32.2). Of adolescents between 12 and 19 years old, 16.1% were overweight (BMI >95%) and 14.8% were at risk for overweight (BMI 85%–95%). Therefore, a total of 30.9% of adolescents had a BMI > the 85th percentile. More Mexican-Americans were overweight (22.5%) than non-Hispanic blacks (21.1%) or non-Hispanic whites (13.7%). More Mexican-American males were overweight than Mexican-American females; more non-Hispanic white males were overweight than non-Hispanic white females; and more non-Hispanic black females were overweight than non-Hispanic black males.
  2. Trends (Table 32.3): Data from the NHANES done in 1976 to 1980, 1988 to 1994, and 1999 to 2002 have shown that the prevalence of overweight in 12- to 19-year olds increased from 5% to 10.5% to 16.1%, respectively; the prevalence of overweight in males increased from 4.8% to 11.3% to 16.7%, respectively and the prevalence of overweight in females increased from 5.6% to 9.7% to 15.4%, respectively.
  3. Adults: NHANES data for adults aged 20 through 74 years have also shown an increase in prevalence of obesity. In the period 1988 to 1994, 23.3% of American adults

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20 years or older were estimated to be obese while in NHANES 1999 to 2002, 30.4% of adults were obese. There was a dramatic increase from prior studies in all race and sex groups.

TABLE 32.3
Overweight in Children Aged 6 to 11 and Adolescents Aged 12 to 19 Years (United States National Health and Nutrition Examination Surveys)

 

NHANES II 1976–1980

NHANES III 1988–1994

NHANES 1999–2002

Adapted from Ogden CL, Flegal KM, Carroll MD, et al. Prevalence and trends in overweight among US children and adolescents, 1999–2000. JAMA 2002;288:1728, and Hedley AA, Ogden CL, Johnson CL, et al. Prevalence of overweight and obesity among US children, adolescents, and adults, 1999–2002. JAMA 2004;291:2847.

Females 6–11

6.4

11.0

14.7

Females 12–19

5.3

9.7

15.4

Males 6–11

6.6

11.6

16.9

Males 12–19

4.8

11.3

16.7

Males/females 6–11

6.5

11.3

15.8

Males/females 12–19

5.0

10.5

16.1

  1. Fifty percent to eighty-five percent of overweight adolescents will be obese adults. If a child is overweight at 12 years of age, the odds are 4:1 against that child attaining an ideal body weight (IBW); if overweight after adolescence, the odds are 28:1 against attaining an IBW. The persistence and severity of overweight as measured by BMI and triceps skinfold thickness in adolescents predicts the severity of obesity in adulthood.
  2. Premature death in women has been associated with higher BMI at age 18 years (van Dam, 2006). From the Nurses Health Study II, a BMI of 30 kg/m2or more at age 18 carried with it almost three times the risk of premature death compared with a BMI between 18.5 and 21.9 kg/m2, and double the risk of those with a BMI of 25 to 29 kg/m2.
  3. Weight-loss practices among American adolescents: In a national study, Serdula et al. (1993) found that 44% of female students and 15% of male students reported that they were trying to lose weight. Students had used the following weight control methods in the 7 days preceding the survey—exercise (51% of female students and 30% of male students), skipping meals (49% and 18%), taking diet pills (4% and 2%), and vomiting (3% and 1%). In a study of 30,000 adolescents in Minnesota (Neumark-Sztainer, 1998), 12% of females and 2% of males reported chronic dieting whereas 30% females and 13% males reported binging, 12% females and 6% males reported self-induced vomiting, and 2% females and 0.5% males reported diuretic or laxative use. In a more recent study of 4,746 Minnesota adolescents, 3.1% of females and 0.9% males stated that they met the criteria for binge eating disorder; 41.2% males and 15% females who identified themselves as meeting criteria for binge eating disorder had BMI >95%. Eighty-five percent to 90% had dieted in the past year and 70% to 80% were currently trying to lose weight (Ackard et al., 2003).

Influence Of Obesity On Health

Complications due to obesity in adolescents include:

  1. Cardiovascular: Dyslipidemias, hypertension.
  2. Endocrinologic: Hyperinsulinism, insulin resistance, impaired glucose tolerance, type 2 diabetes mellitus, menstrual irregularity, and polycystic ovarian syndrome. Metabolic syndrome is a combination of dyslipidemias (high density lipoprotein [HDL] <40 mg/dL, triglycerides >110 mg/dL), elevated blood pressure, fasting glucose >110 mg/dL, and overweight.
  3. Orthopedic: Slipped capital femoral epiphysis, Blount disease.
  4. Respiratory: Sleep apnea, snoring, Pickwickian syndrome, asthma, and obesity hypoventilation syndrome.
  5. Gastroenterologic: Gall bladder disease, steatohepatitis.
  6. Psychological: Depression, eating disorders, social isolation, poor self-esteem.

Future medical problems are usually not a concern of the overweight adolescent, who is more preoccupied with the psychosocial consequences. The overweight adolescent who becomes an obese adult will have more severe obesity than those adults whose obesity began in adulthood. A 50-year follow-up study of overweight adolescents found that the rate of morbidity and mortality from cardiovascular disease was significantly increased compared to their lean counterparts (Must et al., 1992). Moreover, the influence of adolescent overweight on adult morbidity and mortality was independent of the effects of adolescent overweight on adult weight. Excess weight is associated with an increased incidence of cardiovascular disease, type 2 diabetes mellitus, hypertension, stroke, dyslipidemia, sleep apnea, osteoarthritis, and some cancers. However, >80% of the mortality related to complications of obesity occurs in people with a BMI >30 kg/m2.

Medical Evaluation

Medical evaluation includes the assessment of factors that contribute to weight gain, inhibit weight loss, and comorbid factors that exist and can benefit from weight loss or maintenance.

  1. History
  2. Family history of obesity, cardiovascular disease, hyperlipidemia, hypertension, type 2 diabetes mellitus, thyroid disease, and colorectal or breast cancer
  3. Past weight loss efforts
  4. Onset of obesity
  5. Triggers for weight gain (e.g., illness or injury, depression, medication use)
  6. Diet history including diet recall, family-eating patterns
  7. Unhealthy eating attitudes and weight-related behaviors including dieting, binge eating, purging
  8. Exercise history
  9. Sedentary activity time including evaluation of screen time (computer, video games, handheld electronic games)
  10. Medication use or abuse
  11. History of potential secondary causes (e.g., thyroid disease, Cushing disease)

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  1. Full review of systems including headaches (i.e., pseudotumor cerebri), orthopedic complaints, snoring, daytime sleeping, abdominal pain, hip pain, urinary frequency, polydipsia, polyuria, and irregular menses or amenorrhea
  2. Physical examination
  3. Weight, height, and BMI calculation should be plotted on the appropriate CDC growth curves published in 2000 (Ogden, 2002).
  • Short stature suggests hypothyroidism or Cushing syndrome.
  1. Blood pressure should be checked with the appropriate sized cuff.
  2. Waist circumference may be helpful in those older than 20 years.
  3. Triceps skinfolds can be done if the examiner has expertise with this measurement (Table 32.1).
  4. Sexual maturity rating should be determined.
  • Undescended testicles are seen in males with Prader-Willi syndrome.
  • Delayed puberty in females suggests Turner syndrome.
  1. Skin, hair, and ligaments.
  • Acanthosis nigricans suggests insulin resistance and polycystic ovarian syndrome.
  • Striae that are violet in color and located on the abdomen, buttocks, and thighs are suggestive of Cushing syndrome.
  • Hirsutism is suggestive of polycystic ovarian syndrome.
  • Polydactyly suggests Bardet-Biedl syndrome as does mental retardation.
  1. Papilledema suggests pseudotumor cerebri.
  2. Thyromegaly suggests hypothyroidism.
  3. Developmental delay suggests Prader-Willi syndrome or other genetic syndromes.
  4. Laboratory tests
  5. Thyroid-stimulating hormone, thyroxine, fasting blood glucose, fasting lipid profile, and liver function tests.
  6. For evaluation for insulin resistance and type 2 diabetes, particularly if there is acanthosis nigricans or a strong family history of diabetes, a fasting plasma glucose is recommended by the American Diabetes Association. A fasting plasma glucose of 100 to 125 mg/dL represents impaired glucose tolerance, whereas levels of 126 mg/dL or above represents diabetes. Alternative tests include a 2-hour glucose tolerance test and a casual glucose. After the ingestion of a 75-g glucose load, a blood glucose >140 mg/dL at 2 hours reflects impaired glucose tolerance and a blood glucose >200 mg/dL is likely representative of diabetes. A casual glucose of above 200 mg/dL plus polyuria, polydipsia, and weight loss reflect diabetes. Fasting insulin levels and glucose/insulin ratios have also been used to predict insulin resistance.
  7. Patients with polycystic ovarian syndrome may have amenorrhea or irregular menstrual periods, hirsutism, and acne. An elevated free testosterone, DHEAS or androstenedione is helpful in the diagnosis of polycystic ovarian syndrome. An LH : FSH ratio of >3.0 is present in only half of these patients and lacks sensitivity and specificity.
  8. If cushingoid, then 24-hour urine free cortisol and overnight dexamethasone suppression test are in order.
  9. If obstructive sleep apnea is present, overnight oximetry or a sleep study is warranted.

Treatment

Therapy for obesity is a challenge for both the health care provider and the patient of any age. Young adolescents are often more difficult to treat than older adolescents because of the lack of abstract thought and motivation. In general, treatment focuses on control rather than cure, as is so often the case with chronic medical conditions. When is it appropriate to strongly recommend weight reduction? Certainly, adolescents with morbid obesity (those with twice normal weight, BMI >40 kg/m2, or >100 lb [45.5 kg] overweight) are at significant risk for medical problems and need to be encouraged to lose weight. The weight goal should be <85% BMI for age and sex. For many adolescents this can be accomplished by weight maintenance over a period of time, whereas for others a slow 1 lb/month weight loss should be encouraged. It is essential to remember that severe caloric restriction during adolescence, particularly during a growth spurt can halt growth and the progression of puberty. Therefore, understanding where an adolescent is with respect to his or her pubertal development and more specifically to their growth spurt, is critical in developing appropriate weight goals.

Critical areas in assessing treatment readiness in the adolescent include:

  1. Motivation: This is critical for success. Is the teen motivated? Is the desire for weight loss or maintenance someone else's idea?
  2. Support: Is there a supportive social and family framework for weight reduction or maintenance?
  3. Compliance: Is the teen willing to increase physical activity? Is the teen prepared to modify diet?
  4. Realistic goals: Are there realistic goals for weight reduction?

Diet, exercise, behavior modification, and support are still the mainstay of treatment for obesity in adolescents and young adults. The role of medication and bariatric surgery for overweight adolescents is still being evaluated.

Diet

An energy deficit is needed for active weight loss and is a critical part of management. However, diet alone is rarely successful in achieving permanent weight loss. Predicting weight loss for an individual teenager based on caloric intake is difficult and can vary widely. For older adolescents and young adults, a deficit of 250 to 500 kcal/day is associated with a loss of approximately 0.5 to 1 lb/week (0.23–0.45 kg). Greater caloric restrictions are very difficult to maintain. The type of caloric restriction should be well planned and should take into account current food types and intake, eating habits, situation-dependent eating, and family and cultural preferences. To support normal growth and development, there must always be good nutritional balance among the food groups.

Approximate daily energy needs in the postpubertal adolescent can be calculated from the weight in kilograms

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(W) as follows:

The activity factor is 1.2 for a low activity level, 1.4 for a moderate activity level, or 1.6 for a high activity level. The energy requirement to maintain each extra kilogram of body weight is approximately 22 kcal. Therefore, an adolescent who weighs 20 kg more than another needs an additional 440 kcal to maintain that weight.

Various nutritional approaches to weight loss exist and some have been studied. The ketogenic diet or low-carbohydrate diet has been studied in adolescents. Sondike et al. (2003)published a 12-week randomized controlled trial comparing a low-fat diet to a low-carbohydrate diet in adolescents. The low-carbohydrate diet was effective for short-term weight loss without affecting the lipid profile. However, the sample size was small with a brief follow-up period. This diet has not been studied in younger adolescents and the long-term benefits require further study.

A balanced weight reduction diet focusing on healthy lifestyle practices is recommended for the adolescent population and should include the following:

  1. Foods from all five food groups (milk, meat, bread, fruits, and vegetables).
  2. Instructions to eat at least three meals/day.
  3. Instructions to eat less food or calories than previously.
  4. Instructions on ways of preparing low-calorie foods and of substituting foods with fewer calories for high-calorie foods.

One simplification of this diet is the “Traffic Light” approach (Epstein et al., 1998). Green light foods can be eaten freely (nonfat foods, low-fat foods, fruits, vegetables). Yellow light foods are those eaten with caution (low-to-moderate fat foods such as breads, pastas). Red light foods are those to be eaten rarely (nuts, candy). This concrete view can be helpful to both children and adolescents.

Physical Activity

Every weight reduction program should include an increase in physical activity. This can include the following:

  1. Changes in regular activity, such as walking instead of using the bus, using stairs instead of elevators, walking to the television set instead of using a remote control (even minor increases in activity can make a difference overall).
  2. An exercise prescription.
  3. Participation in regular physical activity. Although no specific recommendations for the amount of physical activity has been established for adolescents, the position statement of the American Academy of Pediatrics Committee (2003) on Nutrition on Prevention of Pediatric Overweight and Obesity (2003) clearly encourages families, schools, and communities to promote physical activity.

Cognitive Behavioral Therapy or Behavior Modification Techniques

Cognitive behavioral therapy (CBT) or behavior modification techniques can be effective when used in combination with diet and medical therapies. Penich et al. (1971) and Stunkard et al. (1970) have reviewed this approach. These programs usually contain several components:

  1. A contract and reward system for weight loss.
  2. An initial food diary that contains items such as time spent eating, place, hunger rating, mood, other activity done while eating, food consumed, and amount consumed.
  3. A change in current behavior through eating awareness and a food diary.
  4. Eat three regular meals instead of overeating at dinner and evening.
  5. Eat more slowly; allow the body to signal when it is full.
  6. Eat only at places that are meant for eating (e.g., at the dinner table, in restaurants).
  7. Do not watch television while eating.
  8. Do not eat on the go; sit down to eat.
  9. Learn to differentiate between appetite and hunger.
  10. Eat only when hungry and not just when food is available.
  11. Have a breakout activity when feeling out of control or when eating is related to depression, anxiety, or unhappiness.
  12. Be honest about lapses in control.

Groups

Group participation as part of the weight-loss program may be beneficial. Groups provide encouragement, support, and an opportunity for release of feelings, peer contact, and acceptance.

Although there is no evidence for the effectiveness of structured commercially based weight-loss programs in adolescents, such programs have been shown to provide modest weight loss compared with self-help groups in adults (Heshka et al., 2003). All the structured commercial weight-loss programs studied (ranging from moderately to very restrictive diets) led to a similar amount of weight loss at 1 year, with poor dietary adherence with the more restrictive diets (Dansinger et al., 2005).

Medications for the Treatment of Obesity

The two medications studied in the treatment of adolescent obesity are sibutramine and orlistat. A meta-analysis of pharmacological treatments of adult obesity is available from Li et al. (2005).

  1. Sibutramine—a serotonin, norepinephrine, and dopamine reuptake inhibitor has been studied in overweight adolescents aged 16 years and older.
  2. Dosage: The starting dose is 10 mg once daily, which may be increased after 4 weeks to 15 mg once daily. Daily dosages of 10 and 15 mg have been associated with a weight loss of 10.6 lb (4.8 kg) and 13.4 lb (6 kg), respectively, compared with 4 lb (1.8 kg) for placebo. Individuals are more likely to lose weight if weight loss is demonstrated in the first 4 weeks. Improvement has also been documented in levels of triglyceride, HDL cholesterol, and insulin, and in insulin sensitivity.
  3. Adverse effects: These include headaches, dry mouth, constipation, insomnia, and increases in heart rate and blood pressure. There is no evidence of an association with cardiac valve abnormalities. The medication does not appear to have a high abuse potential.

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Contraindications include anorexia nervosa, hypersensitivity to drug, therapy with monoamine oxidase inhibitors or other serotonergic drugs, coronary heart disease, congestive heart failure, stroke, arrhythmia, uncontrolled hypertension, severe hepatic or renal disease, pregnancy, and lactation. Caution is advised in individuals with a history of seizures. This medication is not indicated for mildly or moderately overweight individuals in the absence of medical complications.

  1. Orlistat—acts as a lipase inhibitor, blocking the absorption of dietary fat by inhibiting gastrointestinal lipases. The medication has no effect on the absorption of carbohydrates, proteins, or phospholipids. It increases fecal fat from 5% to 30%. The use of orlistat has been studied in overweight adolescents aged 12 and older and if tolerated, increases short-term weight loss.
  2. Dosage: 120 mg orally three times a day. In one study in adults, 120 mg of orlistat three times a day was associated with loss of 8.8% to 10.2% of body weight after 1 year, compared with 5.8% to 6.1% for placebos.
  3. Adverse effects: The incidence of adverse effects is similar to that of placebo with the exception of more frequent gastrointestinal complaints. There are no reports of vitamin deficiencies. However, individuals should take a daily multivitamin 2 hours before or after orlistat. Contraindications include malabsorption syndromes, cholestasis, known hypersensitivity, pregnancy, and lactation.

Finally, many of the selective serotonin reuptake inhibitors (SSRIs), including fluoxetine, fluvoxamine, sertraline, and citalopram have been used to decrease binging in patients with binge eating disorder. Sibutramine and topiramate have been found to decrease binging in this population as well.

Gastrointestinal Procedures: Bariatric Surgery

A multidisciplinary group of pediatric and surgical specialists published guidelines for bariatric surgery in adolescents (Inge et al., 2004). Potential candidates include:

  1. Skeletally mature adolescents who have failed at least 6 months of dietary weight management
  2. Adolescents whose BMI is >40 kg/m2with serious comorbid conditions that would resolve with sustained weight loss
  3. Adolescents who have a supportive family and personal maturity

Those with BMI >50 kg/m2 with less serious comorbid conditions could be considered. A multidisciplinary team including the bariatric surgeon and specialists in adolescent obesity, psychology, and nutrition are essential to the process. Potential procedures include Roux-en-Y gastric bypass and laparoscopic adjustable gastric banding. The Roux-en-Y gastric bypass is performed laparoscopically, separating the stomach into a small-volume upper pouch (limiting oral intake) and connects the stomach to a limb of jejunum. Approximately 85% of individuals lose at least 50% of their excess weight at 4 years. Micronutrient supplementation is needed. The laparoscopic adjustable band uses a small silastic band around the upper stomach that is inflated with saline through a subcutaneous port. Although reversible and removable, there have been technical issues as well as patient management problems. A meta-analysis of surgical treatment of obese adults is available from Maggard et al. (2005).

Although similar guidelines are not available for adolescents, the American College of Physicians published evidence-based practice guidelines for the treatment of obesity in adults (Snow et al., 2005). The following are the recommendations:

  • Counsel obese adults about lifestyle and behavioral changes in order to achieve the patient's goal for weight loss.
  • Offer pharmacological therapy to those obese adults who have not reached their weight loss goal through diet and exercise.
  • Discuss the pros and cons of approved medications used for weight loss including side effects, lack of evidence for long-term safety, and temporary nature of weight loss with these medications.
  • Consider bariatric surgery for obese adults with BMI >40 kg/m2who have failed a weight-loss program or who have obesity-related comorbid medical problems.
  • Refer patients who choose to have bariatric surgery to a medical center with experienced surgeons who perform this surgery frequently.

Prevention

  • Encourage healthy nutritional practices in early puberty when there is programmed propensity to increase fat cells. This includes encouraging adequate intake of calcium, increased fruits and vegetables, and decreased amount of saturated fat. Reduce the intake of soft drinks and caloric dense food.
  • Identify unhealthy eating attitudes and harmful eating behaviors including dieting, overeating, and binging, all of which are associated with overweight.
  • Encourage a lifestyle of activity and participation rather than one of inactivity and observation. Increase the frequency and intensity of activity during physical education classes in schools. Increase access to recreational facilities within communities.
  • Discourage television viewing and other sedentary pastimes. Reducing television, videotape, and video game use may be a promising population-based approach to prevention of childhood obesity.
  • Support better food choices in schools including school lunches and vending machines.
  • Encourage family time including meals and activities.

Web Sites

For Teenagers and Parents

http://www.health.gov/dietaryguidelines/. Dietary guidelines.

http://win.niddk.nih.gov/. Weight-control Information Network (WIN), national information service of the NIH, National Institute of Diabetes and Digestive and Kidney Diseases.

http://www.nhlbi.nih.gov/health/public/heart/hbp/dash. DASH, the Dietary Approaches to Stop Hypertension.

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http://www.shapeup.org/sua. Shape up America! Founded by former Surgeon General Everett Koop, M.D., promoting healthy weight and increased physical exercise.

http://www.usda.gov/cnpp. Center for Nutrition Policy and Promotion.

http://www.eatright.org. American Dietetic Association Web site for nutrition information, food pyramid and good nutrition reading list

http://www.kidshealth.org/teen/food fitness/dieting/obesity.html. Information for teens reviewed by physicians, sponsored by Nemours Foundation.

http://www.kidshealth.org/parent/nutrition_fit/nutrition/overweight_obesity.html. Information for parents, reviewed by physicians, sponsored by Nemours Foundation.

http://www.aap.org/obesity/family.htm. Information for parents on childhood obesity.

http://www.bam.gov. CDC Web site for teens on health issues including obesity and nutrition.

For Health Professionals

http://www.nhlbi.nih.gov/guidelines/obesity/ob_home.htm. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, from NIH.

http://www.niddk.nih.gov/health/nutrit/nutrit.htm. National Institute for Diabetes and Digestive and Kidney Diseases, publications on weight control. http://www.aafp.org/afp/990215ap/861.html. From American Family Physician, evaluation and treatment of childhood obesity.

http://www.obesity.org/subs/childhood/. American Obesity Association.

http://www.aap.org/obesity. Resources for physicians on obesity.

http://www.nasso.org. The obesity society, a scientific society for research, education, advocacy and organizational development whose journal is Obesity Research.

http://www.obesityonline.org. Online collection of evidence based obesity education resources.

References and Additional Readings

Ackard DM, Neumark-Sztainer D, Story M, et al. Overeating among adolescents: prevalence and associations with weight-related characteristics and psychological health.Pediatrics 2003;111:67.

Allison DB, Fontaine KR, Manson JE, et al. Annual deaths attributable to obesity in the United States. JAMA 1999;282:1530.

Alpert MA, Hashimi MW. Obesity and the heart. Am J Med Sci 1993;306:117.

Appolinario JC, Bacaltchuk J, Sichieri R, et al. A randomized, double-blind, placebo-controlled study of sibutramine in the treatment of binge-eating disorder. Arch Gen Psychiatry 2003;60(11):1109.

Arnold LM, McElroy SL, Hudson JI, et al. A placebo-controlled, randomized trial of fluoxetine in the treatment of binge-eating disorder. J Clin Psychiatr 2002;63(11):1028.

Balsinger BM, Luque-de Leon E, Sarr MG. Surgical treatment of obesity: who is an appropriate candidate? Mayo Clin Proc 1997;72:551.

Barlow S, Dietz W. Obesity evaluation and treatment: expert committee recommendations. Pediatrics 1998;102:e29.

Berkowitz RI, Fujioka K, Daniels SR, et al. Effects of Sibutramine treatment in adolescents: a randomized trial. Ann Intern Med 2006;145(2):81.

Berkowitz RI, Wadden TA, Tershakovec AM, et al. Behavior therapy and sibutramine for the treatment of adolescent obesity. JAMA 2003;289:1805.

Braunschweig CL, Gomez S, Liang H, et al. Obesity and risk factors for the metabolic syndrome among low-income urban African American school children: the rule rather than the exception? Am J Clin Nutr 2005;81:970.

Bray GA, Blackburn GL, Ferguson JM, et al. Sibutramine produces dose-related weight loss. Obes Res 1999;7:189.

Brownell KD, Rodin J. The dieting maelstrom: is it possible and advisable to lose weight? Am Psychol 1994;49:781.

Bullen BA, Reed RB, Mayer J. Physical activity of obese and non-obese adolescent girls appraised by motion picture sampling. Am J Clin Nutr 1964;14:211.

Callahan T, Mansfield J. Type II diabetes mellitus in adolescents. Curr Opin Pediatr 2000;12:310.

Canadian Task Force on the Periodic Health Examination. Periodic health examination, 1994 update: 1. Obesity in childhood. Can Med Assoc J 1994;15:871.

Chanoine JP, Hampl S, Jensen C, et al. Effect of orlistat on weight and body composition in obese adolescents. JAMA 2005;293:2873.

Clement K, Boutin P, Froguel P. Genetics of obesity. Am J Pharmacogenomics 2002;2:177.

Consensus Development Conference Panel. Gastrointestinal surgery for severe obesity. Ann Intern Med 1991;115:956.

van Dam RM, Willett WC, Manson JE, et al. The relationship between overweight in adolescence and premature death in women. Ann Intern Med 2006;145(2):91.

Daniels SR, Khoury PR, Morrison JA. The utility of body mass index as a measure of body fatness in children and adolescents: differences by race and gender. Pediatrics1997;99:804.

Dansinger ML, Gleason JA, Griffith JL, et al. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction; a randomized trial. JAMA 2005;293:43.

Davidson MH, Hauptman J, DiGirolamo M, et al. Weight control and risk factor reduction in obese subjects treated for 2 years with orlistat: a randomized controlled trial. JAMA1999;281:235.

Dennison BA, Erb TA, Jenkins PL. Television viewing and television in bedroom associated with overweight risk among low-income preschool children. Pediatrics 2002;109:1028.

Dickerson LM, Carek PJ. Drug therapy for obesity. Am Fam Physician 2000;61:2131.

Dietz WH. Therapeutic strategies in childhood obesity. Horm Res 1993;39:86.

Dietz WH. What constitutes successful weight management in adolescents? Ann Intern Med 2006;145(2):145.

Dietz WH, Bellizzi MC. Introduction: the use of body mass index to assess obesity in children. Am J Clin Nutr 1999;70:123s.

Dietz WH, Robinson TN. Overweight children and adolescents. N Engl J Med 2005;352(20):2100.

DuRant RH, Baranowski T, Johnson M, et al. The relationship among television watching, physical activity, and body composition of young children. Pediatrics 1994;94:449.

Epstein LH, Myers MD, Raynor HA, et al. Treatment of pediatric obesity. Pediatrics 1998;101(suppl):554.

P.475

 

Epstein LH, Roemmich JN, Paluch RA, et al. Influence of changes in sedentary behavior on energy and macronutrient intake in youth. Am J Clin Nutr 2005;81:361.

Farooqi IS, O'Rahilly S. Recent advances in the genetics of severe childhood obesity. Arch Dis Child 2000;83:31.

Flegal KM. Defining obesity in children and adolescents: epidemiologic approaches. Crit Rev Food Sci Nutr 1993;33:307.

Flegal KM, Graubard BI, Williamson DF, et al. Excess deaths associated with underweight, overweight and obesity. JAMA 2005;293:1861.

Fontaine KR, Redden DT, Wang C, et al. Years of life lost due to obesity. JAMA 2003;289:187.

Freedman DS, Khan LK, Serdula MK, et al. Relation of age at menarche to race, time period, and anthropometric dimensions: the Bogalusa heart study. Pediatrics2002;110(4):e43.

Freedman DS, Khan LK, Serdula MK, et al. The relation of childhood BMI to adult adiposity: the Bogalusa heart study. Pediatrics 2005;115(1):22.

Galuska DA, Will JC, Serdula MK, et al. Are health care professionals advising obese patients to lose weight. JAMA 1999;282:1576.

Gortmaker SL, Must A, Perrin JM, et al. Social and economic consequences of overweight in adolescence and young adulthood. N Engl J Med 1993;329:1008.

Gutin B, Yin Z, Humphries MC, et al. Relations of moderate and vigorous physical activity to fitness and fatness in adolescents. Am J Clin Nutr 2005;81:746.

Hannon TS, Rao G, Arslanian SA. Childhood obesity and type 2 diabetes mellitus. Pediatrics 2005;116:473.

Hedley AA, Ogden CL, Johnson CL, et al. Prevalence of overweight and obesity among U.S. children, adolescents, and adults, 1999–2002. JAMA 2004;291:2847.

Herbold N, Frates S. Update of nutrition guidelines for the teen trends and concerns. Curr Opin Pediatr 2000;12:303.

Hernandez B, Gortmaker SL, Colditz GA, et al. Association of obesity with physical activity, television programs and other forms of video viewing among children in Mexico City.Int J Obes Relat Metab Disord 1999;23:845.

Heshka S, Anderson JW, Atkinson RL, et al. Weight loss with self-help compared with a structured commercial program; a randomized trial. JAMA 2003;289:1792.

Heyden S, Hames CG, Bartel A, et al. Weight and weight history in relation to cerebrovascular and ischemic heart disease. Arch Intern Med 1971;128:956.

Heymsfield SB, Greenberg AS, Fujioka K, et al. Recombinant leptin for weight loss in obese and lean adults: a randomized, controlled, dose-escalation trial. JAMA 1999;282:1568.

Hill J, Peters J. Environmental contributions to the obesity epidemic. Science 1998;280:1371.

Himes JH, Dietz WH. Guidelines for overweight in adolescent preventive services: recommendations from an expert committee. Am J Clin Nutr 1994;59:307.

Hirschler V, Aranda C, de Lujan Calcagno M, et al. Can waist circumference identify children with the metabolic syndrome? Arch Pediatr Adolesc Med 2005;159:740.

Hubert HB, Feinleib M, McNamara PM, et al. Obesity as an independent risk factor for cardiovascular disease: a 26-year follow-up of participants in the Framingham Heart Study.Circulation 1983;67:968.

Hudson JI, McElroy SL, Raymond NC, et al. Fluvoxamine in the treatment of binge-eating disorder: a multicenter placebo-controlled, double-blind trial. Am J Psychiatry1998;155(12):1756.

Inge TH, Krebs NF, Garcia VF, et al. Bariatric surgery for severely overweight adolescents: concerns and recommendations. Pediatrics 2004;114:217.

Janz KF, Nielsen DH, Cassady SL, et al. Cross-validation of the Slaughter skinfold equations for children and adolescents. Med Sci Sports Exerc 1993;25:1070.

Kannel WB, Brand N, Skinner JJ Jr, et al. Relationship of adiposity to blood pressure and development of hypertension: Framingham study. Ann Intern Med 1967;67:48.

Kimm SYS, Barton BA, Obarzanek E, et al. Racial divergence in adiposity during adolescence: the NHLBI growth and health study. Pediatrics 2000;107(3):e34.

Krebs NF, Jacobson MS. American Academy of Pediatrics Committee on Nutrition. Prevention of pediatric overweight and obesity. Pediatrics 2003;112:424.

Lean ME. Sibutramine: a review of clinical efficacy. Int J Obes Relat Metab Disord 1997;21(Suppl 1):S30.

Lee IM, Manson JE, Hennekens CH, et al. Body weight and mortality: a 27-year follow-up of middle-aged men. JAMA 1993;270:2823.

Leibel RL, Rosenbaum M, Hirsch J. Changes in energy expenditure resulting from altered body weight. N Engl J Med 1995;332:621.

Li Z, Maglione M, Tu W, et al. Meta-analysis: pharmacologic treatment of obesity. Ann Intern Med 2005;142:532.

Lowe MR, Miller-Kovach K, Frye N, et al. An initial evaluation of a commercial weight loss program: short-term effects on weight, eating behavior, and mood. Obes Res 1999;7:51.

MacMahon SW, Wilcken EEL, MacDonald GJ. The effect of weight reduction on left ventricular mass: a randomized controlled trial in young, overweight hypertensive patients. N Engl J Med 1986;314:334.

Maggard MA, Shugarman LR, Suttorp M, et al. Meta-analysis: surgical treatment of obesity. Ann Intern Med 2005;142:547.

McCarthy HD, Jarrett KV, Crawley HF. The development of waist circumference percentiles in British children aged 5.0–16.9 y. Eur J Clin Nutr 2001;55:902.

McElroy SL, Shapira NA, Arnold LM, et al. Topiramate in the long-term treatment of binge-eating disorder associated with obesity. J Clin Psychiatry 2004;65(11):1463.

Must A, Jacques PF, Dallal GE, et al. Long-term morbidity and mortality of overweight adolescents: a follow-up of the Harvard growth study of 1922–1935. N Engl J Med1992;327:1350.

Must A, Spandano J, Coakley EH, et al. The disease burden associated with overweight and obesity. JAMA 1999;282:1523.

National Heart, Lung and Blood Institute, National Institutes of Health. Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults [Executive Summary]. Arch Intern Med 1998;158:1855. Available at www.nhlbi.nih.gov/nhlbi/nhlbi.htm.

National Institutes of Health, Consensus Development Panel on the Health Implications of Obesity. Health implications of obesity. Ann Intern Med 1985;103:147.

National Institutes of Health Technology Assessment Conference. Methods for voluntary weight loss and control. Ann Intern Med 1993;119:641.

National Task Force on the Prevention and Treatment of Obesity. Very low-calorie diets. JAMA 1993;270:967.

Neumark-Sztainer D, Story M, Resnick MD, Blum RW. Lessons learned about adolescent nutrition from the Minnesota Adolescent Health Survey. J Am Diet Assoc. 1998;98(12):1449–56.

Ogden CL, Flegal KM, Carroll MD, et al. Prevalence and trends in overweight among US children and adolescents, 1999–2000. JAMA 2002;288:1728.

Ogden CL, Kuczmarski RJ, Flegal KM, et al. Centers for Disease Control and Prevention 2000 growth charts for the United States: improvements to the 1977 National Center for Health Statistics version. Pediatrics 2002;109:45.

P.476

 

Penich S, Filion R, Fox S, et al. Behavior modification in the treatment of obesity. Psychosom Med 1971;33:49.

Pietrobelli A, Faith MS, Allison DB, et al. Body mass index as a measure of adiposity among children and adolescents: a validation study. J Pediatr 1998;132:204.

Pinhas-Hamiel O, Zeitler P. Type II diabetes in adolescents: no longer rare. Pediatr Rev 1998;19:434.

Rand CS, Macgregor AM. Adolescents having obesity surgery: a 6-year follow-up. South Med J 1994;87:1208.

Ravussin E, Lillioja S, Knowler WC, et al. Reduced rate of energy expenditure as a risk factor for body weight gain. N Engl J Med 1988;318:467.

Revicki DA, Israel RG. Relationship between body mass indices and measures of body adiposity. Am J Public Health 1986;76:992.

Robinson TN. Reducing children's television viewing to prevent obesity: a randomized controlled trial. JAMA 1999;282:1561.

Robinson TN, Hammer LD, Killen JD, et al. Does television viewing increase obesity and reduce physical activity? Cross-sectional and longitudinal analyses among adolescent girls.Pediatrics 1993;91:273.

Rosenblatt E. Weight-loss programs: pluses and minuses of commercial and self-help groups. Postgrad Med 1988;83:137.

Rumpel C, Harris TB. The influence of weight on adolescent self-esteem. J Psychoso Res 1994;38:547.

Sargent JD, Blanchflower DG. Obesity and stature in adolescence and earnings in young adulthood: analysis of a British birth cohort. Arch Pediatr Adolesc Med 1994;148:681.

Schapira DV, Clark RA, Wolff PA, et al. Visceral obesity and breast cancer risk. Cancer 1994;74:632.

Serdula MK, Collins ME, Williamson DF, et al. Weight control practices of U.S. adolescents and adults. Ann Intern Med 1993;119:667.

Sinha R, Fisch G, Teague B, et al. Prevalence of impaired glucose tolerance among children and adolescents with marked obesity. N Engl J Med 2002;346:802.

Slaughter MH, Lohman TG, Boileau RA, et al. Skinfold equations for estimation of body fatness in children and youth. Hum Biol 1988;60:709.

Smith JC, Sorey WH, Quebedeau D, et al. The use of body mass index to monitor treatment of obese adolescents. J Adolesc Health 1997;20:466.

Snow V, Barry P, Fitterman N, et al. Pharmacologic and surgical management of obesity in primary care; a clinical practice guideline from the American College of Physicians. Ann Intern Med 2005;142:525.

Sondike SB, Copperman N, Jacobson MS. Effects of a lowcarbohydrate diet on weight loss and cardiovascular risk factors in overweight adolescents. J Pediatr 2003;142:253.

Sterner TG, Burke EL. Body fat assessment: a comparison of visual estimation and skinfold techniques. Phys Sportsmed 1986;14:101.

Stunkard A. New theories for eating disorders: behavior modification of obesity and anorexia nervosa. Arch Gen Psychiatry 1972;26:391.

Stunkard AJ, Harris JR, Pedersen NL, et al. The bodymass index of twins who have been reared apart. N Engl J Med 1990;322:1483.

Stunkard A, Levine H, Fox S. The management of obesity. Arch Intern Med 1970;125:1067.

Stunkard A, Mendelson M. Obesity and the body image: parts 1 and 2. Am J Psychiatry 1967;123:1296,1443.

Stunkard AJ, Sorensen TI, Hanis C, et al. An adoption study of human obesity. N Engl J Med 1986;314:193.

Styne DM. Obesity in childhood: what's activity got to do with it? Am J Clin Nutr 2005;81:337.

Sun SS, Schubert CM, Liang R, et al. Is sexual maturity occurring earlier among U.S. children? J Adolesc Health 2005;37:345.

Swallen KC, Reither EN, Haas SA, et al. Overweight, obesity, and health-related quality of life among adolescents: the national longitudinal study of adolescent health. Pediatrics2005;115(2):340.

Troiano RP, Flegal KM. Overweight children and adolescents: description, epidemiology and demographics. Pediatrics 1998;101:497.

Tsai AG, Wadden TA. Systematic review: an evaluation of major commercial weight loss programs in the United States. Ann Intern Med 2005;142:56.

Volkmar FR, Stunkard AJ, Woolston J, et al. High attrition rates in commercial weight reduction programs. Arch Intern Med 1981;141:426.

Vuguin P, Saenger P, Dimartino-Nardi J. Fasting glucose insulin ration: a useful measure of insulin resistance in girls with premature adrenarche. J Clin Endocrinol Metab2001;86:4618.

Weiss R, Dziura J, Burgert TS, et al. Obesity and the metabolic syndrome in children and adolescents. N Engl J Med 2004;350:2362.

Willi S, Oexmann M, Wright N, et al. The effects of a highprotein, low-fat, ketogenic diet on adolescents with morbid obesity: body composition, blood chemistries, and sleep abnormalities. Pediatrics 1998;101:61.

Yanovski SZ, Yanovski JA. Obesity. N Engl J Med 2002;346:591.

Yanovski JA, Yanovski SZ. Treatment of pediatric and adolescent obesity (editorial). JAMA 2003;289:1851.