INTRODUCTION — Adolescence is a nutritionally vulnerable life phase. Poor eating habits formed during adolescence can lead to obesity and diet-related diseases in later years. In addition, the high incidence of dieting behaviors can contribute to nutritional inadequacies and to the development of eating disorders. Primary care providers are in an optimal position to provide nutrition screening, counseling to the adolescent patient and caregivers, and referral to a dietitian if needed.
This topic review discusses characteristic adolescent eating habits, including skipping meals, fast food consumption, frequent snacking, and dieting behaviors [1-4]. The nutritional requirements for adolescents are discussed separately. (See "Estimation of dietary energy requirements in children and adolescents".)
OVERVIEW OF CHALLENGES AND TRENDS — Nutritional needs during adolescence are increased because of the increased growth rate and changes in body composition associated with puberty [1,5,6]. The dramatic increase in energy and nutrient requirements coincides with other factors that may affect adolescents' food choices, nutrient intake, and thus, nutritional status. These factors, including the quest for independence and acceptance by peers, increased mobility, greater time spent at school and/or work activities, and preoccupation with self-image, contribute to the erratic and unhealthy eating behaviors that are common during adolescence [1,7]. In addition, adolescents may have formed beliefs about their cultural foods and eating habits that reflect their family's notions of healthy and unhealthy foods, which may or may not be accurate [8]. Unhealthy eating habits are seen in adolescents in the United States and many other countries [9-13].
Sound nutrition can play a role in the prevention of several chronic diseases, including obesity, coronary heart disease, certain types of cancer, stroke, and type 2 diabetes [14-21]. For this reason, nutrition remains an important objective for Healthy People 2030 campaign [22]. Establishing and maintaining healthy eating behaviors during childhood and adolescence can help to prevent diet-related chronic diseases [23-26]. (See "Healthy diet in adults".)
●Nutritional deficits – National and population-based surveys in the United States have found that adolescents often fail to meet dietary recommendations for overall nutritional status and for specific nutrient intakes [27-33]. Many adolescents receive a higher proportion of energy from fat and/or added sugar and have a lower intake of a vitamin A, folic acid, fiber, iron, calcium, vitamin D, and zinc than is recommended [34-40]. The low intake of iron and calcium among adolescent girls is of particular concern. Iron deficiency can impair cognitive function and physical performance, and inadequate calcium intake may increase fracture risk during adolescence and the risk of developing osteoporosis in later life [41-46]. Vitamin D deficiency is increasingly prevalent and is associated with decreased bone density and probably fracture risk [47,48]. (See "Iron requirements and iron deficiency in adolescents" and "Bone health and calcium requirements in adolescents" and "Vitamin D insufficiency and deficiency in children and adolescents".)
Eating habits vary widely among adolescents and also display some general trends over time, reflecting sociocultural trends in food availability and nutritional goals. An analysis of United States National Health and Nutrition Examination Survey (NHANES) data between 1999 and 2016 noted a modest improvement in diet quality (adjusted for energy intake), but more than two-thirds of adolescents still had poor diet quality as defined by the American Heart Association and less than 1 percent had ideal diet quality [33]. Consumption of sugar-sweetened beverages and added sugars generally decreased and sodium intake increased. Another study using NHANES data found that American adolescents consumed approximately two-thirds of their caloric intake from highly processed foods, such as chips, cookies, candy, soft drinks, and ready-to-eat products (such as pizza, instant soup, hot dogs, and chicken nuggets) [49]. Moreover, highly processed food intake was inversely associated with metrics of cardiovascular health, based on a composite score of excess body weight, smoking, physical activity, blood pressure, cholesterol, and dysglycemia. This is consistent with studies in adults, which link consumption of highly processed foods to risks for cardiovascular disease and type 2 diabetes. (See "Healthy diet in adults", section on 'Highly processed foods'.)
●Knowledge deficits – During adolescence, young people are in a transition period when they gradually take over the responsibility for their own eating habits. Knowledge is one of the factors necessary for a healthy transition of responsibility. Questionnaires used to assess nutrition knowledge demonstrate that more than two-thirds of adolescents (especially boys, those from rural environments, and those who are overweight) have unsatisfactory knowledge about dietary recommendations, sources of nutrients, diet-disease relationships, and dietary habits [50]. In this group, television was the main source of information about nutrition for adolescents. A meta-analysis demonstrated a significant albeit small effect of media food marketing on unhealthy eating behaviors in preadolescents and adolescents [51].
Parents and caregivers have the opportunity to influence their child's dietary intake in a variety of ways, the most important of which are the decisions made about what foods are available within their home [52]. Nutrition education interventions focusing on spices and herbs also may be an effective tool to improve diet quality and healthy eating attitudes, especially among urban and African-American adolescents [53]. The addition of spices and herbs was associated with modest improvement in the consumption of grain and protein food products, as well as attitudes toward eating vegetables, whole grains, lean protein, and low-fat dairy products.
SKIPPING MEALS — Adolescents may skip meals because of irregular schedules [54]. Breakfast and lunch are the meals most often missed, but social, school, and work activities can cause evening meals to be missed as well [1,55-57].
●Prevalence – On any given day, 12 to 50 percent of adolescents skip breakfast; older adolescents (those age 15 to 18 years) are twice as likely to skip breakfast as are younger adolescents, and girls are more likely to do so than are boys (35 versus 25 percent in one study) [1,55,58-61]. In a 2015 nationally representative survey of high school students, only 36.3 percent ate breakfast for all seven days before the survey. Subgroups that were more likely to consume breakfast all seven days were the 9th grade students (39.6 percent) compared with 12th grade students (33.8 percent) and boys (40.5 percent) compared with girls (32.1 percent) [30]. More than one-half of the adolescents participating in the National Adolescent School Health Survey reported that they ate breakfast less than twice per week [2]. Reasons for skipping breakfast include lack of time, early school activities, proximity of fast food outlets and grocery stores near schools [10], or a poor appetite first thing in the morning [1,62].
●Consequences of skipping breakfast – The omission of breakfast can affect school performance and the overall quality of the diet [63,64]. In one cross-sectional and longitudinal study of school breakfast programs, students with greater participation in the breakfast program had greater increases in math grades, decreases in child and teacher ratings of psychosocial problems, and decreases in absence and tardiness than did children with less participation [65]. In another large-scale survey of schoolchildren from nine states, hungry children and children at risk for hunger were more likely to have impaired function, hyperactivity, absenteeism, and tardiness than were not-hungry children [66].
Total nutrient intakes are lower among adolescents who skip breakfast as compared with those who consume breakfast [1,9,64,67]. Adolescent breakfast consumers have a higher intake of calories; fiber; vitamins A, B6, and B12; iron; and calcium and better overall eating habits than do adolescents who skip breakfast [56,58,61,68-71]. When breakfast is consumed, it contributes to approximately one-fourth (21 to 26 percent) of total daily energy intake [72,73]. The foods that typically are skipped with breakfast include fruits, breads, and calcium- and iron-rich foods (milk and iron-fortified cereals, respectively) [28,56,58,74-76]. Adolescents who skip breakfast tend not to compensate for these losses at other meals [74,77,78].
●Family-based meals – Adolescents' busy lifestyles often conflict with family mealtimes [1,79,80]. The frequency of having meals with the family decreases during adolescence, and family meals are associated with higher diet quality [4,28,75,81-83]. One large study in children aged 9 to 14 years demonstrated that those who ate meals with their families most or all of the time have healthier diets than do those who rarely or never ate with their families [84]. Adolescents who eat with their families tend to consume less fried food and soft drinks and more fruits, vegetables, and whole grains [84]. A five-year longitudinal study with 1700 adolescents found that family meal frequency during adolescence predicts higher intakes of fruits and dark-green and orange vegetables and lower intakes of soft drinks during early adulthood [28].
●Effects on body weight – Adolescents, particularly females, may use skipping meals as a strategy for weight control [3,85,86]. However, the calories that are "saved" by skipping meals are often made up through heavy snacking on nutrient-poor foods or by overeating at the next meal [87,88]. This eating pattern tends to impair nutrition because high-fat/energy-dense snack foods rarely compensate for the nutritional value of the meals that are skipped [55]. Moreover, multiple studies have documented an association between skipping meals and weight gain [7,10,56,67,89-92].Conversely, higher eating frequency (eg, not skipping meals) is associated with lower body weight status in adolescents, especially among boys [93].
Possible explanations for the association between meal skipping and weight gain include [91]:
•Adolescents perceive that they are reducing energy intake by skipping meals, when in fact they are not
•Individuals with a propensity to gain weight are more likely to skip meals to compensate
•Skipping meals is a marker for other poor nutrition and physical activity habits [94,95]
In any case, it appears that meal skipping for weight control may result in an unhealthy diet and may cause unintended weight gain during adolescence [56,68,85,92,96]. (See 'Dieting' below.)
Counseling — Adolescents should be advised not to skip meals, particularly breakfast. Eating regular meals, using the ChooseMyPlate tool as a guide, can increase total nutrient intake as well as the mean number and amount of servings from food groups that typically are low in adolescents' diets (eg, iron- and calcium-rich foods, fruits, and vegetables) [3,97,98]. (See 'Dietary balance' below.)
Adolescents should be informed that skipping meals does not help with weight control and indeed may promote weight gain, as discussed above.
SNACKING
●Prevalence – Most adolescents snack [55,99,100]. After approximately 12 years of age, teenagers seldom conform to a regular pattern of three meals per day; more than one-half of teens admit to eating at least five times per day [3,55,59,100]. Snacks are a major source of energy and nutrients, providing nearly one-quarter to one-third of total energy intake for many adolescents [3,101,102]. In one study from Canada, after-school snacks represented 13 percent of total daily energy intake; the largest energy contributors were energy-dense, nutrient-poor foods such as cookies, sugar-sweetened beverages, and sweets [103].
●Consequences – Depending upon their timing and composition, between-meal snacks can contribute in negative or positive ways to the adolescent diet [104]. Poorly timed snacks that are high in calories and low in nutrients (ie, "junk food") may blunt the adolescent's mealtime appetite and replace nutritious foods that are needed for growth and development [1-3].
Studies have highlighted the negative impact of high-fat and high-sugar foods on brain function, resulting in cognitive impairment and altered reward processing, which may predispose individuals to dysregulated eating and impulsive behaviors [105]. Sugar-sweetened beverages often have a negative impact on diet quality [37,40] and also contribute to weight gain [106,107]. In a national survey in the United States, sugar-sweetened beverages or fruit juice comprised 10 to 15 percent of the calories consumed by children and adolescents [108]. Increased intake of sugar-sweetened beverages also may be an important predictor of cardiometabolic risk independent of weight status [109]. Moreover, dietary sodium is associated with higher intake of sugar-sweetened beverages, identifying a possible link between dietary sodium and excess energy intake [110]. In contrast, healthy snacks can help meet the increased energy and nutrient needs of adolescence [5]. Snacks that are nutrient-dense (ie, have a ratio of nutrients to calories similar to that of meals) can help to fill the "nutritional gaps" (eg, fiber, vitamin A, calcium, and iron) that remain after traditional meals [1,3,111].
●Association with sedentary activity – Television viewing is associated with increased snacking among children and adolescents and also with obesity [60,112]. Spending more than 120 minutes watching television is associated with significantly higher intakes of total fat and polyunsaturated fat and lower intake of several minerals and vitamins [113]. Adolescents with high media exposure, including television and video and computer games, were more likely to drink sugar-sweetened beverages rather than water or milk [114]. Exposure to advertising of poor-quality snack foods appears to be an important mechanism for the association between television viewing and food intake or obesity. In an analysis of food advertisements shown during television programs designed for children, more than 90 percent of the advertised foods were high in fat, sodium, or added sugars or low in overall nutrients. The most commonly advertised food included ready-to-eat cereals and cereal bars, fast food, snack foods (chips, cookies, fruit rolls), and candy [115]. (See "Definition, epidemiology, and etiology of obesity in children and adolescents", section on 'Environmental factors'.)
Counseling — Adolescents should be taught how to improve the overall quality of their diets with nutritious snacks [1,2]. Instead of selecting high-fat, high-sugar, nutrient-poor snacks such as candy, pie, cakes, cookies, and chips, adolescents should select foods that are lower in fat and more nutrient-dense, such as [116]:
●Fresh fruit or vegetables with low-fat yogurt dip
●Iron-fortified cereal and low-fat milk
●String cheese
●Cheese and crackers
●Low-fat frozen yogurt
●Calcium-fortified cereal bars and juices
●Vegetarian pizza
FAST FOODS
●Prevalence – As they become more independent, adolescents increasingly make their own decisions about what, when, where, and with whom to eat [14]. With busy after-school schedules, adolescents frequently eat away from home. Fast foods are popular choices because they are inexpensive, familiar, and available at almost any hour of the day or night and because many adolescents socialize with their peers at fast food establishments [2,117,118]. Individuals younger than 18 years of age account for more than 80 percent of fast food restaurant visits [118,119]. The most popular food items consumed by adolescents at fast food establishments include french fries, sandwiches (especially hamburgers and cheeseburgers), pizza, and Mexican dishes (tacos and burritos) [120]. The most common beverage choices are carbonated soft drinks, coffee/tea, and milk (in that order) [120]. (See "Fast food for children and adolescents".)
●Consequences – The impact of fast food on the diets of adolescents depends upon the frequency of visits to fast food restaurants and the food choices that are made, but fast food generally has adverse effects on diet quality [121-123]. Traditional fast foods are low in iron, calcium, vitamins A and C, fiber, and folic acid and high in energy, sodium, cholesterol, and total and saturated fat (table 1) [1,35,124-127]. Fat provides more than 50 percent of the calories in many fast food items [1,117]. In Project Eat (Eating Among Teens), the total energy intake of adolescents who reported eating at a fast food restaurant more than three times in the preceding week was almost 40 percent higher than those who did not [117]. Increased fast food consumption was associated with greater intakes of soft drinks and lower intakes of fruits, vegetables, grains, and milk [128,129]. Fast food consumption also has a modest association with overweight status among adults [130,131] and adolescent girls [132]. (See "Fast food for children and adolescents", section on 'Association with obesity'.)
Counseling — Fast foods are a way of life for many adolescents. It is important to teach adolescents how to make wise food choices at fast food restaurants. Many fast food restaurants offer lower-fat and nutrient-dense food choices in addition to traditional selections, and a meal that provides important nutrients for adolescent growth and development can be ordered [133]. Healthier choices include salad bars, baked potatoes, steamed vegetables, low-fat frozen yogurt, and lower-fat sandwiches (table 1) [1,2]. (See "Fast food for children and adolescents".)
In addition, because healthy snacks can compensate for nutrient deficiencies, adolescents should supplement fast foods with nutritious snacks, including calcium-rich foods and fresh fruits and vegetables [2,111,134].
DIETARY BALANCE
Goals — In the United States, the recommended diet composition is based upon the Dietary Guidelines for Americans [135], which are taught by the United States Department of Agriculture (USDA) "MyPlate" tool [136]. The tool was developed to individualize dietary guidelines according to age, sex, and activity level; it replaces the previous pyramid-based model. MyPlate focuses on five food groups (fruits, vegetables, grains, dairy, and protein) rather than the six groups outlined in the food group pyramid and does not have a category for "discretionary calories." The plate provides a visual tool for dietary balance; individuals are encouraged to cover one-half of their plate with fruits and vegetables.
Examples of recommendations for individuals at several different calorie levels are provided in the table (table 2). (See "Dietary history and recommended dietary intake in children".)
Vegetables and fruits — For an adolescent with low activity levels, the dietary recommendations translate to approximately 2.5 cups of vegetables and 1.5 cups of fruit daily for girls (1800 calorie diet) and 3 cups of vegetables and 2 cups of fruit daily for boys (2200 calorie diet).
Actual consumption of fruits and vegetables is well below these targets [137]. Using dietary recall data from the 2007 to 2010 National Health and Nutrition Examination Survey (NHANES) applied to the 2013 Youth Risk Behavior Surveillance Survey, an estimated 8.5 percent of high school students met the USDA fruit recommendations and 2.1 percent met the vegetable recommendations. The median consumption of fruits and vegetables was 0.5 cup and 0.8 cup equivalents per day (100 percent fruit juice and fried potatoes were not included) [31]. In a 2010 survey of high school students, the median consumption of fruits and vegetables was 1.2 times per day for both vegetables and fruits (100 percent fruit juice was included as a fruit) [138]. Consumption decreased between the beginning and end of high school. Overall, approximately 30 percent of high school students consumed fruit less than once daily and 30 percent consumed vegetables less than once daily. Low consumption of fruits and vegetables is associated with higher intakes of fast food. (See 'Fast foods' above.)
Dairy — The dietary guidelines outlined in MyPlate promote a high intake of dairy products (approximately three to four servings/day for adolescents); low-fat or fat-free products are recommended.
●Calcium – The recommended dietary allowance for calcium is 1300 mg for males and females 9 to 18 years of age. The recommended three to four servings/day of dairy products provides 900 to 1200 mg of calcium, and many adolescents fail to meet this goal [30]. Calcium intake can be increased through foods that are naturally rich in calcium, calcium-fortified foods, and calcium supplements. (See "Bone health and calcium requirements in adolescents", section on 'Calcium intake'.)
●Vitamin D – The recommended intake for vitamin D is 600 international units daily. Some individuals appear to require higher vitamin D intake to maintain serum concentrations in the target range. (See "Vitamin D insufficiency and deficiency in children and adolescents", section on 'Prevention in older children and adolescents'.)
The recommended three servings of fortified dairy products provides approximately 350 international units of vitamin D [139], which is approximately one-half of the recommended daily intake for adolescents. Thus, intake of vitamin D-fortified foods (breads, cereals, and juices), fatty fish (salmon, mackerel, sardines), and supplementation of vitamin D may be needed, particularly for adolescents who have less than the recommended three servings of dairy products daily or for those with low serum concentrations of 25-hydroxyvitamin D.
In the United States, the prevalence of vitamin D deficiency or insufficiency (defined in these studies as serum 25-hydroxyvitamin D concentrations <20 ng/mL [50 nmol/L]) is approximately 15 percent in adolescents [140]. However, the prevalence varies considerably among different countries and subpopulations because of differences in risk factors, including diet, skin pigmentation, sun exposure, and obesity.
DIETING — It is common for adolescents to be unhappy with and self-conscious about their changing bodies [141]. In many cultures, thinness, no matter how unrealistic, is perceived as the desired body shape, particularly for females. To avoid becoming overweight and to fit in, many adolescents attempt to lose weight by regulating their food intake [14,142].
Adolescents indicate the following reasons for dieting: feeling "too fat," teasing by peers, pressure from family members, advice of a coach or sports instructor, wanting to look better (ie, thin), and desire to improve health [143-147].
Definition and associated eating patterns — In the discussion below, we use the term "dieting" to describe the manipulation of food intake and food choices that are specifically driven by weight concerns rather than health concerns. This type of dieting is distinct from efforts to adopt healthy eating and other lifestyle behaviors (ie, physical exercise) that are recommended to optimize nutrition and body weight as part of long-term health goals.
Dieting and disordered eating behaviors in adolescents include [85,86,143,147-150]:
●Exclusion of specific foods or food groups
●Adopting reduced-energy diets or fad diets
●Skipping meals
●Binge eating
●Fasting
●Self-induced vomiting
●Using laxatives, diet pills, and diuretics
●Excessive exercising
In a survey of adolescents in the United States, the most common weight loss behaviors included exercising (84 percent); drinking a lot of water (52 percent); eating less "junk" foods or fast foods (45 percent); and increasing intake of fruits, vegetables, and salads (45 percent) [150]. In a separate older survey, disordered eating behaviors (self-induced vomiting and binge eating) were reported by 13 percent of the girls and 7 percent of the boys [143]. (See "Eating disorders: Overview of epidemiology, clinical features, and diagnosis".)
Prevalence — A history of dieting can be obtained in approximately 40 to 70 percent of adolescents [30,86,151-154]. More females than males diet (45 versus 20 percent in one study) [85,143,150], and the sex difference increases significantly with age (56 percent of girls in grades 9 through 12 versus 36 percent of girls in grades 5 to 8) [85,143,152]. Dieting is more common among female adolescents because they tend to be more dissatisfied with their weight than are their male counterparts [85,155,156]. Unfortunately, many adolescent females perceive the normal pubertal weight gain as becoming "fat" and engage in dieting behaviors in an attempt to reverse or slow down the process [157]. Weight concerns and dieting are so common among female adolescents that they are considered to be normative [141,158].
Of particular concern is the degree of dieting among adolescent females who are of normal weight. Many of these girls have dissatisfaction with their bodies that stems from unrealistic perceptions of a healthy body shape and/or body weight [85,153,159,160].
The frequency of dieting varies by region and by nation. In a 1997/1998 World Health Organization (WHO) report of 120,000 students aged 11, 13, and 15 years in 26 European countries, the United States, and Canada, dieting was most common among adolescents in the United States, Israel, and Austria [152].
The observations that adolescents often perceive themselves to be overweight even when they are not and that they frequently use unhealthy dieting behaviors when they try to lose weight have been shown in a large population study [150].
Adverse effects on nutrition — Dieting behaviors can compromise intake of energy and nutrients that are essential for adolescents' growth and development. Most adolescents diet mainly by restricting food, either by excluding foods or entire food groups that are perceived as "fattening" (eg, meats, eggs, and milk and dairy products) and/or by skipping meals [161,162] (see 'Skipping meals' above). The result is a diet that is low in several major nutrients that are already marginal in many adolescents' diets (eg, iron, calcium, and zinc) [44,97,163,164].
●Iron – Female adolescents may have difficulty obtaining the recommended 15 mg of iron per day from food sources if energy intake is low. In particular, reduced intake of animal foods high in iron such as meat and eggs can compromise iron intake [2]. In one study of 12- to 14-year-old British girls, the prevalence of iron-deficiency anemia associated with lower dietary intake of iron was greater among girls who had tried to lose weight than among those who had not (23 percent versus 7 percent, respectively) [165].
●Calcium – Dieting behaviors, particularly skipping meals, can reduce the opportunities to consume foods high in calcium. Milk and dairy products are a major source of calcium for adolescents (table 3) [46,166]. (See "Bone health and calcium requirements in adolescents".)
●Zinc – Avoidance of meats, eggs, and dairy products also can result in inadequate zinc intake. This deficit can be replaced by other foods high in zinc, which include ready-to-eat cereals, legumes, wheat germ, and whole grains (table 4). (See "Zinc deficiency and supplementation in children" and "Vegetarian diets for children", section on 'Zinc'.)
An example of nutrient deficits related to dieting comes from a study of 16- to 17-year-old English girls, comparing those who dieted with those who did not [167]. The mean energy intake of the dieters was less than that of the nondieters (1604 versus 2460 kcal/day). Dieters had significantly lower intakes of breakfast cereal, milk, meat, and meat products. Twice as many dieters as nondieters failed to achieve recommended levels (dietary reference values for United Kingdom) for calcium, zinc, and selenium. Mean daily intakes of the various nutrients are listed below:
●Iron – 12.1 mg versus 13.1 mg among dieters and nondieters, respectively (United Kingdom reference nutrient intake [RNI] = 14.8 mg/day)
●Calcium – 589 mg versus 856 mg among dieters and nondieters, respectively (RNI = 800 mg/day)
●Zinc – 6.6 mg versus 9.1 mg among dieters and nondieters, respectively (RNI = 7 mg/day)
Adverse effects on health — Long-term dieting may have adverse effects on an adolescent's health. Potential adverse effects include irritability, difficulty concentrating, sleep disturbance, muscle wasting, cardiac dysfunction, digestive tract disorders, menstrual irregularity, interruption in growth, delayed sexual maturation, and inadequate bone mass accumulation [147,168-171].
Adolescents who diet frequently are at increased risk for developing eating disorders such as anorexia nervosa and bulimia [163,172-175]. In one three-year prospective study of 1728 14- to 15-year-old adolescents in Australia, girls who dieted at a moderate or severe level [176] were 5 and 18 times more likely to develop an eating disorder, respectively, than were girls who did not diet [173]. A longitudinal study of 2500 adolescents found that adolescent girls who dieted were at twice the risk for engaging in extreme weight-control behaviors (including vomiting or laxative use) and reporting an eating disorder five years later compared with nondieters [163]. Another study of 800 children and adolescents found a significant association between weight-reduction efforts during adolescence and subsequent development of bulimia [177]. (See "Eating disorders: Overview of epidemiology, clinical features, and diagnosis".)
Lack of weight control — Many dieting behaviors used by adolescents in an attempt to lose weight may be ineffective in reducing weight. Paradoxically, these behaviors can lead to binge-eating behaviors and ultimately to weight gain [91,94,147,175,178]. This was shown in an observational study of eating habits in 1902 adolescents who completed a survey about their eating habits at baseline and were followed for ten years [95]. Unhealthy dieting habits such as skipping meals, eating "very little," and the use of food substitutes or diet pills were associated with substantially greater weight gain during the follow-up period even after adjustment for baseline weight status. The body mass index (BMI) increased by 4.63 kg/m2 among adolescents using these unhealthy dieting behaviors, as compared with a BMI increase of 2.29 kg/m2 among those who did not. The results suggest that weight-reduction efforts reported by teenage girls are more likely to result in weight gain than in weight loss. In addition, repeated dieting is highly correlated with cycles of weight loss and gain (ie, "yo-yo" dieting), a risk factor for development of coronary heart disease [97,158].
Counseling
●Supporting weight loss efforts – Preventing or reversing excessive weight gain is an appropriate goal for many adolescents, reflecting the high proportion of overweight and obesity among adolescents in the United States and many other countries [179]. Clinicians can support healthy approaches to weight loss by focusing on a well-balanced diet that includes decreasing consumption of foods with high energy density and increasing exercise [147,180]. (See "Prevention and management of childhood obesity in the primary care setting", section on 'Education to support healthy eating and activity behaviors'.)
●Preventing eating disorders – Health care professionals play a role in educating adolescents about the normal changes in growth and development that occur during adolescence and in helping adolescents understand that self-imposed dieting is neither healthy nor desirable for their growing bodies and may actually increase body weight [147,148,181].
As part of the routine health maintenance examination, primary care providers should ask about body image and dieting patterns and/or use a validated written measure such as the Eating Attitudes Test (table 5). If the adolescent is using unsound dieting or weight loss practices but has no clear symptoms of an eating disorder or significant weight loss, counseling or referral to a dietitian may be sufficient, with close monitoring [97,180]. If an eating disorder is suspected, referral to a multidisciplinary team or professional with expertise in eating disorders is indicated. The team can consist of psychiatrists or psychologists, adolescent medicine clinicians, dietitians, and exercise therapists with the necessary experience in treating eating disorders. (See "Eating disorders: Overview of epidemiology, clinical features, and diagnosis" and "Eating disorders: Overview of prevention and treatment".)
●Promoting dietary balance – Details on dietary balance are discussed above (see 'Dietary balance' above). Key areas for adolescents who diet are:
•To avoid iron deficiency, adolescent females should be advised to consume iron-rich animal foods (ie, lean red meats, chicken, fish, and eggs) or good nonheme sources (ie, iron-fortified cereals, whole grains, dried beans, seeds, and nuts) (table 6) with foods rich in vitamin C (ie, citrus fruits, tomatoes, and pineapple). Some adolescents may require an iron supplement to meet their needs. Laboratory screening for iron deficiency anemia is recommended at least once during adolescence for females and also for any adolescent with risk factors. (See "Iron requirements and iron deficiency in adolescents".)
•Adolescents who avoid milk should be encouraged to include other sources of calcium in their diets, such as low-fat yogurt, cheese, or calcium-fortified foods and beverages (table 3) [46,166]. (See "Bone health and calcium requirements in adolescents".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Healthy diet in children and adolescents".)
SUMMARY AND RECOMMENDATIONS
●Overview – Adolescence is a nutritionally vulnerable time period. Common dietary habits include skipping meals, frequent snacking, consumption of fast foods, dietary imbalance (leading to nutritional deficiencies), and restrictive dieting. Primary care providers are in an optimal position to provide nutritional screening, counseling, and referral to a dietitian or other specialist if needed. The following general approaches are useful for counseling.
●Skipping meals – Stress the importance of eating all meals, particularly breakfast. Adolescents should be informed that skipping meals does not help with weight control and indeed may promote weight gain. (See 'Skipping meals' above.)
●Snacking – Promote nutrient-dense snacks to help fill in nutrient gaps. (See 'Snacking' above.)
●Fast foods – Teach adolescents how to make nutritionally sound choices when faced with an array of foods that may be convenient and appealing but are not necessarily healthy (table 1). (See 'Fast foods' above and "Fast food for children and adolescents".)
●Dietary balance – Use ChooseMyPlate as a guide for a healthy diet and emphasize variety for supplying all the necessary nutrients for growth and development.
•Recommend reduced-fat dairy and animal products, moderate portion sizes, and less frequent consumption of higher-fat items. Along with increased intake of fruits, vegetables, and whole grains, this suggestion can help adolescents achieve dietary guidelines without compromising energy, vitamin, and mineral intakes. (See 'Dietary balance' above.)
•Adolescent girls should be advised to consume iron-rich animal foods or good nonheme sources (table 6) with foods rich in vitamin C. (See "Iron requirements and iron deficiency in adolescents".)
•Educate adolescents, particularly females, about the importance of calcium to bone health, recommended intakes, and good sources of calcium, particularly lower-fat, calcium-rich dairy products and additional sources such as calcium-fortified foods (table 3). (See "Bone health and calcium requirements in adolescents".)
●Dieting – Educate adolescents that "dieting" (the manipulation of food intake and food choices driven by weight concerns rather than health goals) is not healthy. Efforts at weight reduction can compromise nutrition, growth, and health and can increase the risk for the development of an eating disorder. Moreover, dieting behaviors are often associated with weight gain. (See 'Dieting' above.)
•Avoid categorizing foods as "good," "bad," "safe," or "fattening"; focus on foods that are recommended rather than on foods to avoid.
•Emphasize that no one body type is ideal and that adolescents' bodies develop at different rates; stress the importance of body diversity.
•Explain the importance of healthy eating habits to one's health, appearance, and energy.
•Be alert for unhealthy eating patterns, and refer to a dietitian or other specialist as appropriate. If an eating disorder is suspected, referral to a multidisciplinary team or clinician with special expertise in eating disorders is required.
Strategies to support healthy approaches to weight control are discussed separately. (See "Prevention and management of childhood obesity in the primary care setting".)
