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Anorexia Nervosa (AN)

Prof. Yael Letzer, The Faculty of Social Welfare and Health Sciences at the University of Haifa; the Eating Disorders Center at Rambam Health Care Campus.
14 July 2025

This article uses feminine language because most people affected by the disorder are girls. However, the information is relevant to boys, young adults, men, and women of all ages.

Anorexia nervosa is marked by a constant focus on food, body image, and weight, along with harmful behaviors aimed at losing weight, such as being underweight and denying how thin the person really is.

Diagnosis

  • Significantly restricting food intake to about 500–600 calories per day, leading to a body weight far below what is considered healthy for their age, sex, and physical health.

  • Intense fear of gaining weight or becoming fat, resulting in extreme food restriction, even when the person is already underweight. This often includes excessive exercise to lose weight.

  • Strong denial of being extremely thin (underweight).

  • Distorted perception of body weight and appearance. Despite being very thin, the person feels and sees themselves as overweight.

Types

Restricting type

A situation where, in the last 3 months, weight loss has mainly happened due to strict food intake and too much exercise.

Binge-eating/purging type

A condition where, in the past 3 months, a person has not only limited their eating but also experienced uncontrollable binge eating episodes and repeatedly engaged in self-induced vomiting, using laxatives, diuretics, or enemas, or both.

Severity levels

The severity of anorexia nervosa is defined by the body mass index (BMI), that is, the ratio between height squared (in meters) and weight (in kilograms):

BMI Severity Level
17 and above Mild
16–16.99 Moderate
15–15.99 Severe
Below 15 Extreme

Statistics

Anorexia nervosa affects about 0.5% to 1% of the general population. It is most common among teenage girls, who account for about 90% of those diagnosed. Many also have other mental health issues, particularly anxiety disorders, mood disorders, and obsessive-compulsive disorders.

The disorder usually starts in early to late adolescence, with around 85% of cases beginning between the ages of 12 and 18.

Mortality

Anorexia nervosa has the highest mortality rate of all mental health disorders, with 6% to 20% of those affected eventually dying from it. Many people with anorexia resist treatment and deny they have a problem, which means they either don't get care or have trouble sticking with treatment. Unfortunately, this often leads to death—either from malnutrition, complications related to the illness, or suicide. It's estimated that about 20% of deaths related to anorexia are due to suicide, a rate 18 times higher than that of the general population.