. Disorders of Eating

Disorders of Eating

DISORDERED EATING

Kim Peter Norman

Disordered eating can be defined operationally as any eating behavior, or food or body image obsession, that negatively affects health, work, or relationships. This may include restrictive dieting or fasting, abuse of laxatives or appetite suppressants including caffeine and nicotine, skipping meals or avoiding meals with family and friends, overuse of meal supplements, excessive exercising (“exercise bulimia”), chewing then spitting out food, or infrequent binging or purging. Adolescents obsessed with body image may endanger themselves by abusing bodybuilding supplements and performance-enhancing drugs, including steroids, or may relentlessly pursue cosmetic surgery, including liposuction. Disordered eating also includes unsafe dieting techniques such as severe caloric restriction and “zero-carb” diets. Disordered eating is often not recognized because the person suffering may not look ill and does not consider his or her behavior as rising to the level of an eating disorder. In fact, both overweight and athletic youth are most at risk for developing disordered eating. Children with disordered eating may engage in dieting or fasting that seems unnecessary, avoid eating and eating situations, secretly binge, or make overly critical statements about their own body weight, shape, or size.

Disordered eating thus spans a wide spectrum of maladaptive behaviors and attitudes rooted in dissatisfied body image and unhealthy eating habits. These attitudes and behaviors may not meet diagnostic criteria for anorexia nervosa, bulimia nervosa, body dysmorphic disorder (a disorder characterized by severe hatred of one’s body), or eating disorder not otherwise specified (EDNOS), but they may adversely affect health. Disordered eating may be encouraged by athletic coaches advocating bodybuilding and weight control (up to 62% of female and 33% of male athletes engage in disordered eating, according to the National Athletic Trainers Association) or by parents who themselves have disordered eating and overemphasize thinness. Pediatricians encouraging weight loss may unintentionally be supporting disordered eating habits.

Disordered eating, especially binge eating, occurs prominently in one third to one half of adolescent obesity cases. Seventy-nine percent of overweight adolescents admit to unhealthy weight control behaviors, and 17% admit to severe behaviors such as extreme fasting, use of diet pills, and/or purging.¹

Adolescents with disordered eating are at higher risk for growth, hearing, sleep, and headache problems and are more likely to report depressive symptoms, including suicide ideation, poor body image, and low self-esteem. Boys with disordered eating report higher incidences of physical and sexual abuse than their peers, and girls with disordered eating are more likely report histories of molestation and to engage in risky sexual behaviors and substance abuse.² Early detection and treatment is vital to prevent the harmful effects of disordered eating as well as to prevent their escalation into full-blown eating disorders. Recognizable signs of disordered eating almost always precede diagnoses of anorexia and bulimia nervosa. Early detection may be hindered by infrequent visits to a pediatrician, too little time during visits to obtain a thorough history, and reluctance by pediatricians to intervene if a child does not meet full criteria for a diagnosable eating disorder.

Body dissatisfaction starts early. In a well-replicated study of 200 elementary school children between the ages of 8 and 10, 55% of girls and 35% of boys were dissatisfied with their weights.³ Body dissatisfaction increases with age, peaking during adolescence. Reports of disordered eating correspondingly increase from 14.5% during early adolescence to 23.9% during late adolescence.⁴ Unnecessary calorie counting, fasting, and overexercise are so widespread in high schools and college campuses that such behaviors have become widely accepted as normal by adolescents and young adults.

The fashion industry’s promotion of skeletal beauty and the current social focus on obesity increase the pressure on children to be thin. An abundance of evidence suggests that bulimia, and possibly anorexia nervosa, are culture-bound phenomena, with incidences increasing in accordance with exposure to Western culture.⁵ There is also evidence to suggest a genetic predisposition to disordered eating because these behaviors tend to run in families and twin studies show a greater concordance between identical rather than fraternal twins raised apart.

Pediatricians can play a major role in the prevention of disordered eating. The American Academy of Pediatrics⁶ issued a policy statement in 2003 recommending that pediatricians educate themselves in the signs and symptoms of disordered eating and be careful not to foster overaggressive dieting and exercising while counseling children about the risks of obesity and benefits of fitness. Pediatricians were also advised to familiarize themselves with screening and counseling guidelines; monitor height, weight, and body mass index; and learn when to refer to nutritionists and eating disorder specialists. Pediatricians can recommend regular family meals (adolescent girls who frequently eat family meals are less likely to develop disordered eating habits than are those who do not),⁷ and encourage athletic family activities.

EATING DISORDERS

Sara M. Buckelew and Andrea K. Garber

Eating disorders are complex mental health disorders with significant physiological effects and an associated environmental overlay. They occur most commonly in adolescent girls and young adult women; however, males are also affected. It was previously thought that Caucasian girls of high socioeconomic status were primarily affected, but in the United States, eating disorders occur in all socioeconomic classes, races, and ethnicities.⁸ Eating disorders are diagnosed using clinical criteria established by the American Psychiatric Association, as listed in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition.⁹ The disorders currently recognized are anorexia nervosa, bulimia nervosa, and eating disorder not otherwise specified, which includes binge eating disorder. Eating disorders fall on the extreme end of the eating behavior spectrum, with healthy eating patterns at the other end and disordered eating, or unhealthy dieting practices, falling somewhere in the middle.

Table 73-1. Diagnostic Criteria for Anorexia Nervosa

Refusal to maintain a minimally normal body weight for age and height.

Intense fear of weight gain or becoming fat, although underweight.

Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight.

In postmenarcheal females, amenorrhea; that is, the absence of at least 3 consecutive menstrual cycles.

Anorexia subtypes

Restricting type: During the current episode of anorexia nervosa, the person has not regularly engaged in binge eating or purging behavior (ie, self-induced vomiting or the misuse of laxatives, diuretics, or enemas).

Binge eating/purging subtype: During the current episode of anorexia nervosa, the person has regularly engaged in binge eating or purging behavior (ie, self-induced vomiting or the misuse of laxatives, diuretics, or enemas).

Source: Adapted from American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Association; 1994.

EPIDEMIOLOGY, SPECIFIC POPULATIONS AT RISK, AND ASSOCIATED DISORDERS

Anorexia nervosa (AN) is an eating disorder characterized by food restriction that typically results in extreme weight loss. As shown in Table 73-1, the diagnostic criteria for AN include low weight, distorted perception of body shape and size, intense fear of weight gain, and amenorrhea. While many of the complications associated with AN are due to malnutrition (see Chapter 29), patients are often in denial about the seriousness of their degree of weight loss. AN typically affects adolescent girls, with an average prevalence of 0.5% to 3.7% in young women.⁹ The diagnosis is most often made in early to middle adolescence. Critical risk periods appear to be developmental transition (eg, a transition to middle/junior high school, high school, or college) and a decision to embark on diets.

Bulimia nervosa (BN) is characterized by binge and purge behavior and typically affects 1.1% to 4.2% of adolescent/young adult women.⁹ The word bulimia means a condition characterized by perpetual insatiable hunger with bouts of overeating. Table 73-2 shows the diagnostic criteria for BN. Binging episodes are followed by purging, a compensatory behavior that may be vomiting, food restriction, use of laxatives, or compulsive overexercising. Patients with BN report anxiety about gaining weight. However, in contrast to anorexia nervosa, most individuals with BN are normal in weight. Therefore, it is critical to obtain a history of binging and purging behavior to establish the diagnosis. The mean age of onset of BN is 18 years, with most diagnoses made in middle to late adolescence and young adulthood. A history of childhood sexual abuse is more common in patients with BN than in those with AN.¹⁰

Eating disorder not otherwise specified (EDNOS) is a diagnostic category for patients who do not meet the full criteria for anorexia nervosa or bulimia nervosa. For example, a patient who binges infrequently or restricts food but does not have the associated weight loss or amenorrhea may be diagnosed with a “partial eating disorder,” or EDNOS (eTable 73.1 ).

Binge eating disorder (BED) is the newest clinically recognized eating disorder that is currently included under the diagnosis of EDNOS. As shown in Table 73-3, BED is characterized by binging behavior without compensation by purging. Therefore, the majority of patients with BED are overweight. Among adolescents who are actively seeking clinical care for weight management, up to 35% meet the criteria for BED.^11,12 Thus, while it is likely that BED contributes to overweight, studies suggest that overweight may precede the binge eating behavior.¹³

Table 73-2. Diagnostic Criteria for Bulimia Nervosa

Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following:

Eating, in a discrete period of time (eg, within any 2-hour period), an amount of food that is definitely larger than most people would eat during a similar period of time and under similar circumstances.

A sense of lack of control over eating during the episode (eg, a feeling that one cannot stop eating or control what or how much one is eating).

Recurrent inappropriate compensatory behavior to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, enemas, or other medications; fasting; or excessive exercise.

The binge eating and inappropriate compensatory behaviors both occur, on average, at least twice a week for 3 months.

Self-evaluation is unduly influenced by body shape and weight.

The disturbance does not occur exclusively during episodes of anorexia nervosa.

Subtypes of bulimia nervosa

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