Related Health and Development Issues

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Research emphasized the important role that a healthy diet and regular exercise play in optimal physical development in middle childhood. These factors are equally important in a growing adolescent.

Nutritional Needs and Dietary Behavior

Adolescents actually have greater nutritional needs than younger children due to rapid growth, sexual maturation, changes in body composition, skeletal mineralization, and physical activity. These changes result in an increase in total energy needs due to the maintenance of a larger body size. For example, during their peak growth years (11–14 years of age) girls require approximately 2200 kcal/day to sustain growth, whereas boys during ages 15 to 18 require 2500–3000 kcal/day (Mascarenhas, Zemel, Tershakovec, & Stallings, 2001).

In addition to the need for increased calories, adolescents also require more protein, calcium, iron, and zinc in their diet. Although these additional vitamins and nutrients are required for optimal physical growth and development, rarely does the average adolescent consume a diet that consists of these recommended levels. One national study (see ) found that adolescents, particularly girls, demonstrated an insufficient intake of calcium, iron, and vitamins A and C (NHANES III, 1988–1994). When 12,500 children aged 11 to 18 years were surveyed, researchers found that vegetable intake was lower in all age groups than the recommended five servings per day (remember, new guidelines recommend nine servings per day). In fact, french-fried potatoes made up 25% of all vegetables consumed! Intake of simple sugars (like those found in soda and noncitrus juices) exceeded the intake of complex carbohydrates, and more than one-third of the dietary fat was saturated (Gavadini, Sieja-Riz, & Popkin, 2000). Diets poor in essential vitamins and minerals can result in slowed or retarded maturation (zinc deficiency), nonopti mal bone mass accrual or bone mineral density (poor calcium intake), or anemia (iron deficiency).

Adolescents differ from children and adults in that they are more likely to skip meals, eat more meals outside their homes, eat unhealthy snacks that include soda and candy, diet, or consume fast foods. Excessive consumption of simple sugars and saturated fats can contribute to weight gain or obesity in some adolescents (Neumark-Sztainer, Story, Hannan, & Croll, 2002).

Recent findings show that more teens are overweight than ever before (CDC, 2003a). In 1991 the prevalence of overweight adolescents was 11%; by 1999 this had increased to 14%. Recent surveys indicate that the greatest increases in the prevalence of obesity are in minority groups (especially African Americans) and in the proportion of adolescents in the highest percentile of obesity (BMIs > 95th percentile) (Neumark-Sztainer et al., 2002). Health risks associated with obesity in adolescence include increased risk for obesity in adulthood, coronary heart disease in adulthood, and type 2 diabetes. The long-term health care consequences and costs of obesity in adolescents are enormous. Prevention programs encourage not only healthier eating styles but also an increase in regular exercise (U.S. Department of Health and Human Services, 2005).

Disordered Eating Behavior

Adolescence is a developmental period in which individuals experience increased awareness of body image, or how they think and feel about their bodies. A preoccupation with body image and size may be further exacerbated by school transitions and the simultaneous occurrence of puberty, dating, and associated social and academic pressures (Levine, Smolak, Moodey, Shuman, & Hessen, 1994). Research illustrates that body and weight dissatisfaction occurs as early as third grade; is greater in European American than in African American children, females than males, and those with a heterosexual orientation; and increases over time, peaking around eighth or ninth grade (Thompson, Rafiroiu, & Sargent, 2003). These patterns of body dissatisfaction also tend to occur in other affluent countries, such as Hong Kong, Australia, and Sweden (Lam et al., 2002; Lunner et al., 2000).

Body dissatisfaction and weight concerns can lead to unhealthy dieting behaviors, which in turn may promote the development of disordered eating in adolescents (Killen et al., 1996). Studies of middle-school students have reported that between 30 and 55% have dieted at some time (Shisslack et al., 1998) and that, among females, about one-third of normal dieters progress to other problem dieting behaviors (Shisslack, Crago, & Estes, 1995). Problem dieting behavior includes fasting or skipping meals, the use of diet pills, vomiting or using laxatives, smoking cigarettes, or binge eating (Neumark-Sztainer, Story, Falkner, Beuhring, & Resnick, 1999; Croll, Neumark-Sztainer, Story, & Ireland, 2002). These unhealthy dieting behaviors are far more prevalent among adolescents than among children in middle childhood and often go unaddressed because of the varied unmonitored settings within which teenagers consume food. In addition, most unhealthy dieting patterns fall below the criteria for diagnosable eating disorders and may not be viewed as problematic.

Health consequences result from both disturbed eating patterns and eating disorders. Health problems associated with disturbed eating patterns are delayed sexual maturation, menstrual irregularity, constipation, weakness, irritability, sleep problems, and poor concentration (Story & Alton, 1996). Health consequences for eating disorders, however, are much more severe.