Merck Manual

Please confirm that you are a health care professional

honeypot link

Introduction to Eating Disorders


Evelyn Attia

, MD, Columbia University Medical Center;

B. Timothy Walsh

, MD, College of Physicians and Surgeons, Columbia University

Reviewed/Revised Jul 2022 | Modified Sep 2022

Eating disorders involve a persistent disturbance of eating or of behavior related to eating that

  • Alters consumption or absorption of food

  • Significantly impairs physical health and/or psychosocial functioning

Specific eating disorders include

Anorexia nervosa is characterized by a relentless pursuit of thinness, a morbid fear of obesity, a distorted body image, and restriction of intake relative to requirements, leading to a significantly low body weight to the point where health is harmed. This disorder may or may not include purging (eg, self-induced vomiting).

Avoidant/restrictive food intake disorder is characterized by avoidance of food or restriction of food intake that results in significant weight loss, nutritional deficiency, dependence on nutritional support, and/or marked disturbance of psychosocial functioning. But unlike anorexia nervosa and bulimia nervosa, this disorder does not include concern about body shape or weight.

Binge eating disorder is characterized by recurrent episodes in which people consume large amounts of food and feel as if they have lost control. Episodes are not followed by inappropriate compensatory behavior (eg, self-induced vomiting).

Bulimia nervosa is characterized by recurrent episodes of binge eating followed by some form of inappropriate compensatory behavior such as purging (self-induced vomiting, laxative or diuretic abuse), fasting, or driven exercise.

Pica is persistent eating of nonnutritive, nonfood material that is not developmentally appropriate (ie, pica is not diagnosed in children < 2 years) and not part of a cultural tradition.

Rumination disorder is repeated regurgitation of food after eating.

Eating disorders are more common among women, especially younger women, than among men.

See also the American Psychiatric Association’s Practice Guidelines: Treatment of Patients With Eating Disorders, 3rd Edition and guidelines from the National Institute for Clinical Excellence [NICE], December, 2020.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
quiz link

Test your knowledge

Take a Quiz!