Eating Disorders

Eating disorders are psychiatric conditions defined by persistent disturbances in eating behaviour and in the perception of body weight or shape, with major consequences for nutrition and energy metabolism. From the metabolic-endocrine perspective they are notable because altered intake produces wide-ranging hormonal and energy-balance disturbances, and anorexia nervosa carries one of the highest mortality rates among psychiatric disorders.

Definition

Eating disorders are a group of mental disorders characterised by abnormal eating behaviours and related preoccupations with weight or shape that impair physical health or psychosocial functioning; the major categories include anorexia nervosa (restriction leading to low body weight), bulimia nervosa (binge eating with compensatory behaviours), and binge-eating disorder.

Scope

The topic surveys the principal eating disorders, anorexia nervosa, bulimia nervosa, and binge-eating disorder, emphasising their metabolic and endocrine consequences and their place at the interface of psychiatry and energy metabolism. It is a reference overview and does not offer diagnostic criteria for individual use or treatment instructions. A companion node under adolescent mental and behavioural health treats the psychiatric dimension.

Core questions

• How do the major eating disorders differ in behaviour and consequence?
• What endocrine and metabolic disturbances accompany severe undernutrition or binge-purge cycles?
• Why does anorexia nervosa carry such high medical and mortality risk?

Key concepts

• Anorexia nervosa
• Bulimia nervosa
• Binge-eating disorder
• Functional hypothalamic suppression in starvation
• Refeeding syndrome
• Body-image disturbance

Mechanisms

Sustained energy restriction in anorexia nervosa drives the body into a starvation-adapted state: energy expenditure falls, and the hypothalamic-pituitary axes are suppressed, producing low reproductive-hormone output and amenorrhoea, along with disturbances of thyroid, growth, and stress hormones. Loss of fat mass lowers leptin, which contributes to the neuroendocrine suppression. In bulimia nervosa and binge-eating disorder, cycles of binge eating and, in bulimia, compensatory behaviours disturb fluid, electrolyte, and metabolic homeostasis. Rapid nutritional repletion in severely malnourished patients can precipitate dangerous electrolyte and fluid shifts (refeeding syndrome).

Clinical relevance

Eating disorders sit at the intersection of psychiatry and metabolic-endocrine medicine, and their physical consequences make them medically serious. This entry describes the disorders and their metabolic effects for educational reference; it is not a basis for diagnosing or managing any individual, and serious eating disorders require qualified clinical care.

Epidemiology

Eating disorders most commonly begin in adolescence and young adulthood and predominantly affect females, though they occur across sexes and ages. Anorexia nervosa has a notably elevated standardised mortality compared with the general population, reflecting both medical complications and suicide.

Evidence & guidelines

The topic draws on integrative clinical reviews of eating disorders and anorexia nervosa and on standardised diagnostic frameworks. These are narrative reviews and a diagnostic reference; the entry summarises them and does not reproduce operational diagnostic thresholds for self-application.

History

Descriptions of self-starvation date to the nineteenth century, and over the twentieth century eating disorders were progressively defined as distinct psychiatric conditions with serious medical dimensions. Successive diagnostic systems refined their categories, and research increasingly recognised their neuroendocrine and metabolic consequences alongside their psychological features.

Debates

Where does the boundary lie between disordered eating and a diagnosable disorder?

Definitions and thresholds for the eating disorders have shifted across diagnostic systems, reflecting debate over how to capture clinically significant impairment without over- or under-diagnosis.

Key figures

• Janet Treasure
• Cynthia Bulik
• Stephan Zipfel

Seminal works

• treasure-2010
• zipfel-2015

Frequently asked questions

Why are eating disorders relevant to endocrinology and metabolism?

Because disordered intake produces broad hormonal and energy-balance disturbances, such as suppression of reproductive hormones and amenorrhoea in starvation, and because severe cases carry serious metabolic risks including refeeding syndrome.

What are the main eating disorders?

The major categories are anorexia nervosa, bulimia nervosa, and binge-eating disorder, which differ in eating behaviour, weight consequences, and associated complications.