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
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Refusal to maintain a minimally normal body weight for age and height. |
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Intense fear of weight gain or becoming fat, although underweight. |
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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. |
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In postmenarcheal females, amenorrhea; that is, the absence of at least 3 consecutive menstrual cycles. |
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Anorexia subtypes |
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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). |
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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
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Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following: |
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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. |
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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). |
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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. |
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The binge eating and inappropriate compensatory behaviors both occur, on average, at least twice a week for 3 months. |
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Self-evaluation is unduly influenced by body shape and weight. |
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The disturbance does not occur exclusively during episodes of anorexia nervosa. |
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Subtypes of bulimia nervosa |
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Purging type: During the current episode of bulimia nervosa, the person has regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas. |
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Nonpurging type: During the current episode of bulimia nervosa, the person has used other inappropriate compensatory behaviors, such as fasting or excessive exercise, but has not regularly engaged in 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.
PATHOPHYSIOLOGY AND GENETICS
The etiology of eating disorders is multifactorial, including genetic, biological, psychological, and sociocultural influences. Eating disorders are highly heritable, with higher rates of concurrence among identical twins and/or first-degree relatives. Studies of twins estimate a heritability of 30% to 50% for anorexia nervosa.14 Although no specific genes have been implicated, altered levels of several hormones (such as leptin) and neuropeptides (such as serotonin) have been documented in patients with eating disorders. Biological factors such as these are likely to both contribute to the development of the eating disorder and result from the associated behaviors, namely starvation and binging. The psychological factors associated with anorexia nervosa include perfectionism, anxiety, obsessive behavior, and low self-esteem. bulimia nervosa is associated with psychological factors including depression, anxiety, low self-esteem, personality disorders, disturbances in social functioning (eg, inability to have meaningful interpersonal relationships resulting in isolation from normal daily events), substance abuse, and suicidal behavior. Sociocultural factors include the thin ideal, valued in the United States since the early 20th century and increasingly in developing nations today. Internalization of this ideal, including the belief that thinness will bring happiness and success, is associated with poor body image, dieting behavior, and further preoccupation with thinness. Some organized efforts have been made to address this problem. For example, at least 2 countries have instituted body mass index (BMI) limits for participation in runway modeling during fashion weeks. However, the established limit of 18.0 kg/m2 still constitutes extreme thinness and is defined as underweight by the World Health Organization.15 The Council for Fashion Designers in America opted not to create body mass index limits for models in the United States.
Table 73-3. Research Criteria for Binge Eating Disorder
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Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following: |
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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 in a similar period of time under similar circumstances; and |
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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). |
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The binge eating episodes are associated with at least 3 of the following: |
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Eating much more rapidly than normal |
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Eating until feeling uncomfortably full |
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Eating large amounts of food when not feeling physically hungry |
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Eating alone because of being embarrassed by how much one is eating |
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Feeling disgusted with oneself, depressed, or feeling very guilty after overeating |
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Marked distress regarding binge eating. |
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The binge eating occurs, on average, at least 2 days a week for 6 months. |
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The binge eating is not associated with the regular use of inappropriate compensatory behaviors (eg, purging, fasting, excessive exercise) and does not occur exclusively during the course of anorexia nervosa or bulimia nervosa. |
Source: Adapted from American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Association; 1994.
CLINICAL FEATURES AND DIFFERENTIAL DIAGNOSIS
An eating disorder should be suspected any time an adolescent loses significant weight, fails to gain appropriate weight, or develops food avoidance. Symptoms and findings include hypothermia, fatigue, edema, stunting of growth, delayed puberty, oligomenorrhea or amenorrhea, lanugo and hair loss, brittle nails and hair, tooth decay and gingivitis, Russell sign (calluses on the back of the hand from abrasions when inducing vomiting), salivary gland enlargement, muscle cramps and sometimes diarrhea from laxative abuse (see eTable 73.2 ). Most of these physical findings and many of the initial alterations in cognitive functioning are related to the degree of malnutrition, while some result from purging behaviors. Since anorexia nervosa is often characterized by weight loss, other diagnoses such as diabetes mellitus, inflammatory bowel disease, celiac disease, hyperthyroidism, collagen vascular disorders, malignancy, chronic infection such as tuberculosis or human immunodeficiency virus, substance abuse and mental disorders need to be considered (see eTable 73.3 ). A diagnosis of BN requires consideration of additional medical conditions, including a range of gastrointestinal illnesses (eg, gastroesophageal reflux disease, gallbladder disease, ulcers).
DIAGNOSTIC EVALUATION
The diagnosis of an eating disorder is based on the clinical criteria established by the American Psychiatric Association and outlined in Tables 73-1 to 73-3. Obtaining a complete history from the patient and family is critical for establishing a diagnosis (Table 73-4). Physical evaluation of a patient suspected of an eating disorder includes measuring height and weight, calculating body mass index, and plotting these variables on gender-specific curves.16These data points can be compared to prior growth history to assess changes. If growth is normal, points should follow a curve that remains roughly within the same percentiles. Lack of expected weight gain can be an early warning sign of malnutrition, while lack of expected height gain reflects long-term malnutrition. If no historical data are available, the 50th percentile for age and gender can be used to represent average growth. Obtaining vital signs, including heart rate, blood pressure, and orthostatic changes, is necessary to determine the severity of malnutrition. Laboratory testing, including a pregnancy test, an erythrocyte sedimentation rate, liver function tests, thyroid levels, and celiac screen, may be needed to help clarify a diagnosis. In patients with restricting-type anorexia, laboratory values are typically normal, while in patients with purging, electrolyte changes such as significant hypokalemia can be seen. Further evaluation may include an electrocardiogram, particularly to look for arrhythmias and a prolonged QT interval.
COMPLICATIONS
The complications of eating disorders affect multiple biological systems, as shown in Table 73-5. For anorexia nervosa, complications are related to the degree of malnutrition; for bulimia nervosa, complications often arise from purging behavior. One acute complication that emerges during treatment of a malnourished patient is re-feeding syndrome. Refeeding syndrome describes the life-threatening electrolyte shifts that can occur when nutrition is reintroduced (see Chapter 29). In response to carbohydrate and protein feeding, insulin is released and facilitates the transport of nutrients into cells for metabolism. Electrolytes are drawn with the nutrients from the extracellular to the intracellular space, causing a shift in fluids and electrolytes. Dramatic changes in phosphorous, potassium, magnesium, and sodium can result is cardiac arrhythmias, breakdown of muscle, edema, delirium, and death. Thus, severely malnourished patients should be refed under close surveillance in a hospital to monitor for signs of refeeding syndrome.
TREATMENT
The treatment for all eating disorder diagnoses is similar, since those who suffer from anorexia nervosa, bulimia nervosa, and eating disorder not otherwise specified share a preoccupation with food, body weight, and body shape. Treatment for eating disorders typically occurs in the outpatient setting. However, the Society for Adolescent Medicine has developed indications for hospitalization for an adolescent with an eating disorder, including severe malnutrition, electrolyte disturbances, severe bradycardia or other cardiac dysrhythmias, orthostatic changes, acute food refusal, and uncontrollable binging and purging.17 Patients with anorexia nervosa are most likely to meet these criteria. Patients who are failing outpatient treatment may require a higher level of care, including intensive outpatient or partial hospitalization programs or residential care programs.
Table 73-4. Screening and History Questions When an Eating Disorder Is Suspected
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Body image history including |
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How do you feel about how you look? |
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How do your feelings about how you look and about your body affect how you feel? |
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Weight history including |
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What is the most you ever weighed? How tall were you then? When was that? |
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What is the least you ever weighed since menarche? In the past year? How tall were you then? When was that? |
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How often do you weigh yourself? |
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What do you think you ought to weigh? |
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Exercise history including |
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How often do you exercise? For how long? At what level of intensity? |
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How stressed are you if you miss a workout? |
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Dietary practice history including |
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What have you eaten in the last 24 hours? |
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Do you feel full after just starting to eat? |
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Do you skip meals? How often |
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Do you count calories? Do you count fat grams? Do you have any taboo foods (foods you strictly avoid)? |
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Do you have any meal rituals? A set breakfast or lunch? |
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Do you frequently eat in secret or by yourself? |
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Do you have a history of any binging? How often? What types of foods? Are there any triggers to your binges? |
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Do you ever make yourself vomit? How often? Do you use laxatives or diet pills? |
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Mental health history including |
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Have you ever received therapy? Was it useful? |
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History of physical or sexual abuse |
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History of self injurious behavior (ie, cutting) |
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Use of cigarettes, drugs, or alcohol |
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Family history including |
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Family history of obesity or eating disorders |
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Depression, substance abuse, suicide, or other mental illness |
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Review of systems including |
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Menstrual history |
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Gastrointestinal history (ie, history of constipation or diarrhea) |
Source: Adapted from American Academy of Pediatrics. Committee on Adolescence. Identifying and treating eating disorders. Pediatrics. 2003;111(1):204-211.
Table 73-5. Complications of Eating Disorders
Successful treatment typically requires a multidisciplinary team knowledgeable in the care of patients with eating disorders. The team should include (1) a physician who can monitor weight, vital signs, and consequences of malnutrition; (2) a nutritionist who can assist with meal planning and weight restoration; and (3) a therapist who is knowledgeable about treating eating disorders.
The initial medical goal is weight restoration for malnourished patients, a critical first step to enable the patient to benefit from psychological treatment. Long-term goals in the treatment of anorexia nervosa include resumption of normal menstrual periods, healthy eating habits and attitudes, and improved psychological functioning. In treatment of bulimia nervosa, the critical first step is decreasing the frequency of the binging and purging episodes. Medical monitoring is important initially to make certain the patient’s electrolytes are normalized, since purging-induced hypokalemia can lead to cardiac arrhythmias and sudden death. Other important aspects of treatment for bulimia include encouraging regular, moderate physical activity and dental care, as recurrent self-induced vomiting may cause dental erosions and caries.
Nutritional treatment may involve a registered dietitian who can develop a meal plan to provide optimal calories and guide healthy eating habits, such as increased variety or decreased food phobias. Patients should be encouraged to consume regular meals and snacks throughout the day. In patients with binge or purge behaviors, meal skipping should be discouraged, and certain foods might be avoided because these may trigger subsequent binging or purging. Patients with restricting behavior need help increasing variation in their diet. Setting realistic weight goals may also be important. As patients are improving their nutrition and restoring their weight, they often require zinc supplementation and may benefit from a multivitamin in addition to a calcium supplement with vitamin D.
Psychological treatment aims to improve the patient’s body image distortion, self-evaluation of weight or shape and intense fear of becoming fat, and psychiatric comorbidities. Depression, and anxiety and are the most common mental health disorders that co-occur among patients with anorexia nervosa. The psychotherapeutic treatment modality for adolescents with anorexia nervosa that has demonstrated efficacy is family therapy.18 Further research is necessary to determine the benefits of psychotropic medication, including antidepressants and atypical neuroleptic medications.19,20 Antidepressant medications, particularly selective serotonin reuptake inhibitors, may be beneficial in treating coexisting symptoms of depression or obsessive-compulsive disorder. Malnutrition itself may worsen symptoms of anxiety, depression, and obsessive behavior. If symptoms persist following weight restoration, medications may be more effective in treating those symptoms.
For adolescents and adults with bulimia nervosa, cognitive behavior therapy and/or treatment with selective serotonin reuptake inhibitors have demonstrated efficacy. In addition to depression and substance abuse, patients struggling with bulimia nervosa frequently have tremendous shame about their secretive behavior. Cognitive behavior therapy targets thoughts, feelings, and behaviors in order to break the binge/purge cycle and typically includes teaching patients alternate coping skills for anxiety and depressive symptoms. Individuals who have other mental health disorders may need other psychotropic medications or psychotherapy. Chronic binging and purging may worsen symptoms of anxiety, depression, and obsessive behavior. It is important to reevaluate symptoms throughout the treatment and recovery process.
PROGNOSIS OR OUTCOMES
Generally, adolescents have better outcomes than adults, which may be due to a shorter duration of illness among adolescents. Fifty percent of adolescents are thought to have a good outcome; however, recovery can take many years.21 For anorexia nervosa, good prognostic indicators include early identification and entry into treatment, short duration of symptoms, age less than 14 years, anorexia nervosa restricting subtype rather than the binge/purge subtype, and no other mental health disorder (such as depression, anxiety, or substance abuse).22 For bulimia nervosa, studies have shown a full recovery rate that is significantly higher than for anorexia nervosa.23 However, the course of recovery for all of the eating disorders can be long and marked by relapse.22,24 The leading causes of death in patients with anorexia nervosa are suicide and medical complications resulting from malnutrition/starvation. Mortality rates for anorexia nervosa range from 2% to 8%. Mortality associated with bulimia nervosa appears to be significantly less than that due to anorexia nervosa.
PREVENTION
One of the keys to successful treatment of eating disorders is early recognition of the problem and early intervention. Children and adolescents should be weighed at every medical appointment or at least once a year to look for weight loss or growth failure. Longitudinal studies demonstrate that dieting behavior is a risk factor for the development of eating disorders.25,26 Thus, clinicians should screen for dieting behavior. Other risk factors include poor body image27,28 and media exposure.29 Parents, peers, and clinicians can work to prevent eating disorders by promoting healthy eating and physical activity habits rather than focusing on weight or body shape. This can be accomplished by modeling healthy habits, avoiding diets and negative comments about body weight and shape, and encouraging family meals and regular exercise. Media exposure can be limited by parents and/or filtered with proper supervision in the home and clinic setting, where magazines and images depicting healthy body types can be selected.