Overview of eating disorders

Eating disorders are complex, multifactorial conditions characterized by disordered eating and/or weight control behaviors. They are associated with serious negative physical and psychological outcomes, including mortality. Conditions include anorexia nervosa, bulimia nervosa, binge eating disorder, pica, avoidant-restrictive food intake disorder, and rumination disorder. Although any individual can develop an eating disorder, adolescents, athletes, and individuals with comorbid psychiatric conditions and/or a history of trauma are most commonly affected, and these individuals may benefit from routine screening. Individuals with a suspected eating disorder require a comprehensive clinical and laboratory evaluation. The diagnosis is confirmed if the relevant DSM-5 diagnostic criteria for eating disorders are fulfilled. Most patients can be successfully managed in an outpatient setting, however, intermediate care settings such as partial hospitalization programs and residential care may be more appropriate for some patients. Those with red flag features of eating disorders require inpatient medical or psychiatric hospitalization. Management should involve a multidisciplinary team and consists of nutrition support and education, including weight restoration if necessary; psychotherapy (e.g., family-based therapy for adolescents, cognitive behavioral therapy for adults); and, for some patients, pharmacotherapy (e.g., SSRIs for bulimia nervosa, lisdexamfetamine for binge eating disorder). Although complete recovery is possible, a chronic, relapsing course with progressive deterioration is common.

Anorexia nervosa, bulimia nervosa, binge eating disorder, and pica are further detailed separately.

See the respective articles for details.

Binge eating disorder ^[1][2][3][4]

Most common eating disorder in adults in the US

• Key features
  • Recurrent binge eating episodes that are not associated with inappropriate weight compensatory behaviors
  • Pronounced obesity at a young age is common; BMI may also be normal.
  • See also “DSM-5 diagnostic criteria for binge eating disorder.”
• Management
  • Psychotherapy (CBT, interpersonal therapy)
  • Pharmacotherapy may be considered in select patients.
  • Management of comorbidities (e.g., ASCVD prevention)

Weight compensatory behaviors are seen in anorexia nervosa and bulimia nervosa but not in binge eating disorder. ^[1]

Anorexia nervosa and bulimia nervosa

Avoidant restrictive food intake disorder (ARFID) ^[2][3]

Key features (all must be present)

• Avoidance or restriction of food
• ≥ 1 of the following:
  • Significant weight loss; slow growth trajectory (in children)
  • Malnutrition
  • Dependence on nutrition support
  • Impaired psychosocial function
• Features are not explained by body image disturbance, cultural practice, food insecurity, or another medical (e.g., gastrointestinal disease) or psychiatric (e.g., anorexia nervosa) condition.

Management

• See “Initial evaluation of individuals with a suspected eating disorder.”
• Nutritional rehabilitation: similar principles as those used for weight restoration in individuals with anorexia nervosa. ^[2]
• Prevent refeeding syndrome.

Complications of ARFID can be similar to the associated features of severe malnutrition in anorexia nervosa. ^[13]

Rumination disorder ^[5][14]

• A syndrome characterized by recurrent postprandial food regurgitation, without preceding retching ^[14]
• Considered both a functional gastrointestinal disorder and an eating disorder

Pica ^[15][16]

Key features

• Persistent ingestion of nonnutritive nonfood substances
• Complications (e.g., dental damage, GI symptoms) may be present depending on the substance consumed.
• See also “DSM-5 diagnostic criteria for pica.”

Management

• Identify and treat underlying etiology (e.g., iron deficiency, electrolyte abnormalities) and complications (e.g., malnutrition, lead poisoning).
• Behavioral interventions
• Consider SSRIs for refractory symptoms.

• Clinical history ^[2][3]
  • Body image disturbance: distorted perception of one's body and associated dissatisfaction with one's appearance
  • Fear of weight gain
  • Changes in eating and/or exercise patterns
  • Social stressors related to appearance or weight
• Weight fluctuation (e.g., weight loss, inadequate weight gain for height, rapid weight gain) ^[2][3]
• Signs of malnutrition ^{[2][3][5][17]}
  • Neurological: seizures, weakness, dizziness, headaches
  • Cardiovascular: palpitations, cardiac arrhythmias, orthostatic hypotension
  • Metabolic: secondary osteoporosis, stress fractures, euthyroid sick syndrome, hypothermia
  • Secondary amenorrhea, oligomenorrhea, delayed puberty
  • Lanugo
  • Hair loss; brittle nails and hair
  • Muscle wasting
  • Edema
  • Fatigue
  • Poor wound healing
• Signs of recurrent vomiting ^{[2][3][5][17]}
  • Caries and perimylolysis
  • Russell sign
  • Sialadenosis
  • Oropharyngeal petechiae
• Gastrointestinal symptoms ^{[2][3][5][17]}
  • Abdominal discomfort and/or bloating
  • Nausea
  • Vomiting; possible hematemesis
  • Constipation

Relative energy deficiency in sport (RED-S; previously known as female athlete triad) is not itself an eating disorder, but can occur concurrently with or lead to the development of an eating disorder. Ensure all athletes are screened for eating disorders. ^[18]

Indications ^{[2][3][5][19]}

Consider screening the following individuals at increased risk:

• Preteens and adolescents ^[2][5][19]
  • At annual adolescent health visits
  • Evaluation of weight loss
• Athletes (at annual preparticipation screens) ^[20]
• Sexual minority, transgender, and gender diverse youth
• Patients with a: ^[2]
  • History of sexual abuse, childhood adversity, or trauma (including bullying)
  • Chronic disease requiring dietary management
  • Psychiatric disorder and those undergoing an initial psychiatric evaluation

Any individual may be affected by an eating disorder, regardless of race, gender, socioeconomic status, or weight. ^[5][13][21]

Screen for eating disorders in overweight or obese individuals who are losing weight to ensure they are not practicing unhealthy eating and/or exercise patterns. ^[3]

Modalities ^[2][3]

A positive screening must be confirmed with a clinical evaluation for eating disorders. ^[2][19]

Clinical history and examination ^[2][5]

• Assessment of:
  • Eating and exercise behaviors
  • Weight and body image concerns
• Evaluation of weight, height, and BMI trends

SCOFF questionnaire ^[2][19][22]

• The most widely used screening modality for eating disorders
• It is a 5-item questionnaire
  • Can be used as a self-report tool or administered by a physician.
  • Score ≥ 2: Anorexia nervosa or bulimia nervosa is likely.
• Important consideration: May not perform equally well in all populations (e.g., inadequate evidence of its accuracy in men)
• Clinicians may consider supplementing the SCOFF questionnaire with the question, “During the past 3 months, have you had any episodes of excessive eating?”

Other screening modalities ^[2]

These tools may be more sensitive than SCOFF for identifying eating disorders but have not been studied as extensively. ^[2]

• Eating Disorder Diagnostic Scale ^[23]
• Eating Disorder Screen for Primary Care ^[24]
• Screen for Disordered Eating ^[25]

Approach ^[2][3][5]

• Perform a clinical evaluation in patients with any of the following:
  • Positive screening for an eating disorder
  • Suggestive clinical features, e.g.:
    • Rapid change in weight
    • Significant deviation from growth trajectory on CDC longitudinal growth chart
    • Delay in pubertal development
    • Oligomenorrhea or amenorrhea
• Confirm the diagnosis.
  • Make a clinical diagnosis based on the DSM-5 diagnostic criteria for eating disorders.
  • Consider the following based on clinical suspicion:
    • Exclude organic causes of weight changes and eating behaviors.
    • Evaluate for alternative or comorbid psychiatric condition (e.g., depression, OCD).
• Further evaluation
  • Evaluate for complications of eating disorders.
  • Screen for red flag features of eating disorders; determine disposition.
  • Initiate management specific to the disorder.
  • If BMI ≥ 25 kg/m², perform a comprehensive assessment of patients who are overweight or obese.

History ^{[2][3][5][17]}

Perform a detailed review of systems (see “Clinical features”). Obtain collateral history (e.g., from family members, teachers) if possible, especially for adolescents.

Current attitudes and behaviors

• Body image and weight
• Food and eating (e.g., eating habits, types of food consumed, dietary restrictions, bingeing)
• Presence and frequency of inappropriate weight compensatory behaviors

Past history

• Weight trends including highest and lowest weights
• Prior eating disorders and management

Family history

• History of eating disorders and/or weight-related issues
• Physical and mental health conditions
• Special diets
• Attitudes toward exercise and physical appearance

Psychosocial history

• Current stressors (e.g., family, school)
• History of bullying, abuse, or other trauma
• Mood, suicidality, and other psychiatric symptoms or comorbidities
• Substance use

Physical examination ^{[2][3][5][17]}

• Vital signs, including:
  • Temperature
  • Orthostatic vital signs
• Anthropometric measurements, including BMI
• Comprehensive physical exam to assess for signs of malnutrition and/or purging (see “Clinical features”)

Do not assume that bradycardia and/or low blood pressure is due to physical conditioning in athletes with a possible eating disorder. ^[5]

Anthropometric measurements

• Weigh patients while they are wearing a gown and facing away from the scale. ^[5]
• Assess malnutrition severity.
  • Patients 2–20 years of age: Refer to the CDC longitudinal growth charts. ^[13]
  • Adolescents and young adults (< 26 years of age): Severity can be determined using the anthropometric measures detailed in the table below. ^[13][26][27]

Malnutrition can be present in patients with a normal weight and BMI. In adolescents and young adults, preferred measurements of malnutrition include percent median BMI, BMI z-score, and degree of weight loss. ^[5][13]

DSM-5 diagnostic criteria for eating disorders ^[1]

• DSM-5 diagnostic criteria for anorexia nervosa
• DSM-5 diagnostic criteria for bulimia nervosa
• DSM-5 diagnostic criteria for binge eating disorder
• DSM-5 diagnostic criteria for pica

Evaluation for complications

Laboratory studies ^{[2][3][5][17]}

Routine studies

• CBC
• CMP
• Phosphorus
• Magnesium

Additional studies

• Malnutrition and/or significant weight loss
  • Prealbumin
  • TFTs
  • Lipid panel
  • Vitamin D, vitamin B12, iron, thiamine
• Self-induced vomiting: alpha-amylase
• Dehydration: urinalysis (for urine specific gravity) ^[2][5]
• Pancreatitis: lipase
• Oligomenorrhea, amenorrhea, delayed puberty, and/or long-standing eating disorder ^[5][21]
  • All patients: FSH, LH, TSH
  • Women: urine pregnancy test, estradiol, prolactin
  • Men: testosterone

Individuals with recent rapid weight loss, frequent purging, and severe illness are likely to have laboratory abnormalities, regardless of their body weight. Laboratory findings typically normalize following adequate management. ^[2][28]

Hypokalemia can lower the seizure threshold and increase the risk of cardiac arrhythmia.

Normal laboratory study results do not rule out an eating disorder. ^[2]

ECG ^[2][3]

• Indications
  • Patients with any of the following:
    • Abnormal heart rate or blood pressure, orthostasis
    • Use of medications that can prolong the QTc interval
    • Restrictive eating or severe purging
    • Significant weight loss
    • Electrolyte abnormalities
  • Consider for all patients. ^[17]
• Possible findings ^[2]
  • Malnutrition: bradyarrhythmias, QTc prolongation
  • Purging: increased P wave amplitude, wide QRS complex, ST depression, T-wave inversion, SVT, VT

Bone densitometry ^[2]

• Indications
  • Patients with any of the following:
    • Amenorrhea for ≥ 6 months ^[3][21]
    • Hypogonadism ^[5]
    • Stress fracture or long bone fracture ^[5]
    • Male children and adolescents with significant weight loss ^[11]
  • Consider baseline testing for all patients.
• Possible findings: osteopenia, osteoporosis ^[2]

Exclusion of organic causes ^{[2][3][5][17]}

Based on clinical suspicion, evaluate for organic causes of weight changes and eating behaviors, e.g.,

• Thyroid disease or TSH misuse: serum TSH
• IBD: ESR, fecal calprotectin ^[5][17]
• Adrenal insufficiency: serum cortisol ^[3]
• Diabetes: HbA1c
• PCOS: See “Diagnostics” in PCOS. ^[32]
• Celiac disease: celiac panel
• Gastrointestinal infection: stool culture, stool ova and parasites ^[3]
• Stimulant misuse: urine toxicology screen ^[2]

General principles ^[2][5][13]

• Determination of treatment settings should be based on shared decision-making including the patient, family members, and the care team. ^[2]
• Outpatient care is preferred for most patients, if possible.
• Consider the following factors when choosing an initial care setting:
  • Red flag features of eating disorders
  • Laboratory study abnormalities in eating disorders
  • The patient's motivation to change
  • The patient's level of control over disordered behaviors
  • Psychosocial and cultural factors (e.g., presence of social support)
  • Logistical factors (e.g., availability of transportation, insurance barriers)
• Periodically reassess the need for transfer to a higher level of care, e.g., based on :
  • Worsening in any of the above factors
  • Minimal symptom improvement after ≥ 6 weeks of outpatient care (e.g., < 50% reduction in purging behaviors) ^[2]

Most eating disorders can be managed in an outpatient setting. ^[2][33]

The decision to transfer a patient to another care setting should not be based on weight or BMI alone. ^[2]

Red flags supporting hospitalization

The presence of any of the following indicates severe disease and may suggest the need for hospitalization.

Treatment settings

Inpatient care ^[2][3][5]

• Candidates include patients:
  • With red flag features of eating disorders who require continuous medical monitoring and/or intensive management
  • Who require treatment over objection
• Care is provided in either a psychiatric or medical unit, depending on the patient's primary needs.
• Programs with specialized eating disorder care are preferred, if available.

Intermediate care ^[2][3][5]

Candidates include medically stable patients who require intensive guided management by a care team.

• Partial hospitalization
  • Patient lives at home but attends a clinic or hospital facility for ≥ 5 hours per day on ≥ 5 days/week. ^[2]
  • Care team monitors most daily meals.
• Residential treatment
  • Full-time residence at a facility
  • Nursing on-site 24/7 (typically) and a physician on-call 24/7 ^[2]
  • Care team monitors all daily meals.

Outpatient care ^[2][3][5]

Candidates include medically stable patients with motivation to change and good social support.

• Standard outpatient care
  • Intermittent psychotherapy visits (e.g., 1–2 visits/week) ^[2]
  • Meals monitored by caregivers
  • Does not interrupt daily living (e.g., school)
• Intensive outpatient care
  • Partial day psychotherapy visits (e.g., ≥ 3 visits/week for ≥ 3 hours/visit) ^[2]
  • Care team may monitor meals (e.g., one meal daily). ^[2]
  • Minimal interruption to daily living

Outpatients must have weekly weight monitoring, and patients with purging behavior also require regular monitoring of electrolyte levels. ^[2]

Goals ^[2][3][5]

• Restore:
  • Age and height-appropriate weight
  • Growth and pubertal development trajectories (in adolescents and young adults)
• Normalize behaviors around eating and weight, e.g.:
  • Eliminate inappropriate weight compensatory behaviors
  • Reduce number of binge eating episodes
  • Establish regular eating patterns
• Increase self-acceptance and reduce disordered thoughts and beliefs about body weight, size, and shape, and about food.

Components ^[2][3][5]

• Establish an individualized and multidisciplinary treatment plan, including a goal weight if necessary.
• Comanage nutritional support with a dietitian.
• Refer all patients for psychotherapy, e.g., family-based therapy for adolescents and young adults, and cognitive behavioral therapy for adults. ^[16]
• Consider adjunctive pharmacotherapy as needed.
• Identify and manage complications of eating disorders. ^[16]
• See respective articles for details:
  • Treatment of anorexia nervosa
  • Treatment of bulimia nervosa
  • Treatment of binge eating disorder
  • Treatment of pica; complications of pica

Oral cavity disorders ^[29][34]

These may result from repeated self-induced vomiting.

Poor dentition

• Clinical features
  • Gingivitis
  • Dental plaque
  • Erosion of the tooth enamel
• Prevention
  • Encourage routine dental care and regular dental hygienist visits.
  • Avoid tooth brushing immediately after vomiting. ^[3][34]
  • Consider prescribing fluoride toothpaste. ^[3]

Sialadenosis ^[29]

• Clinical features: enlarged parotid (most common), sublingual, and submandibular glands
• Management
  • Initial conservative management: NSAIDs, hot compresses, sialogogues (e.g., sour candies)
  • Persistent enlargement: Consider oral pilocarpine. ^[29]

Lower extremity edema ^[29]

• Etiology: may occur after cessation of purging behaviors
• Management
  • Mild edema: reassurance ^[2]
  • Prevention and management of severe edema: Consider short-term (2–3 weeks) use of spironolactone (off-label) . after sudden cessation of purging behaviors. ^[29][35]

Gastrointestinal dysmotility ^[2][3][29]

• Etiology
  • Starvation; disordered eating patterns
  • Long-term use of stimulant laxatives as an inappropriate weight compensatory behavior ^[36]
  • Initial period of weight restoration in a patient with malnutrition
• Management
  • Bloating or abdominal discomfort: reassurance ; consider promotility drugs (e.g., metoclopramide)
  • Constipation
    • Nonpharmacological management of constipation
    • Bulk-forming laxatives or osmotic laxatives

If metoclopramide is used, monitor for extrapyramidal symptoms. ^[2]

Consider the use of stimulant laxatives only for severe constipation refractory to other treatments; monitor use closely. ^[2]

Decreased bone density ^[2][3]

• Etiology: starvation → hormonal derangements → decreased bone mass density ^[37]
• Clinical features: See “Clinical features of osteoporosis.”
• Management ^[2][5]
  • Weight restoration is the primary means of treatment.
  • Address micronutrient deficiencies.
    • Vitamin D deficiency: Replete appropriately (see “Treatment of vitamin D deficiency”).
    • Inadequate dietary calcium: Consider oral supplementation (see “Repletion regimens for hypocalcemia”). ^[2][38]
  • Consider pharmacotherapy in select patients.
    • Adolescents with bone age ≥ 15 years and bone mineral density z-score < -2.0 who cannot sustain weight gain: transdermal estradiol (off-label) PLUS cyclic oral progesterone (e.g., off-label use of medroxyprogesterone ). ^[2][5]
    • Adults with osteoporosis (especially those with a previous fracture): See “Bisphosphonates for osteoporosis.” ^[2]

Combined oral contraceptives do not improve bone density and should not be used for the exclusive treatment of amenorrhea in patients with eating disorders. ^[21]

Bisphosphonates may have teratogenic effects; use with caution in women of childbearing age. ^[2]

Refeeding syndrome ^[2][17]

• Refeeding syndrome is a syndrome of metabolic derangements and organ dysfunction caused by the reintroduction of nutrition in chronically malnourished individuals. ^[39]
• For details and management, see “Refeeding syndrome.”

We list the most important complications. The selection is not exhaustive.