Anorexia nervosa is a serious eating disorder involving persistent restriction of food intake, intense concern about weight or body shape, and behaviours that prevent the body from getting enough energy and nutrients. It can affect people of every gender, age, body size and background.
Possible signs
- Eating very little, skipping meals or following rigid food rules
- Strong fear of weight gain or distress about body shape
- Frequent weighing, body checking or avoiding eating with others
- Excessive exercise, self-induced vomiting or misuse of laxatives or diuretics
- Weight loss or failure to grow as expected
- Feeling cold, dizzy, tired or unable to concentrate
- Changes in periods, libido, sleep or mood
A person can be medically unwell at any body weight. Appearance alone cannot rule out an eating disorder.
Health effects
Undernutrition can affect the heart, blood pressure, bones, hormones, digestion, kidneys, blood cells and brain. It may cause a slow or irregular heartbeat, fainting, electrolyte disturbance, reduced bone strength, fertility problems, depression and anxiety.
Assessment and treatment
Early assessment improves the chance of recovery. A clinician may check eating patterns, mental health, weight history, pulse, blood pressure, blood tests and an electrocardiogram. Treatment usually combines specialist talking therapy, nutritional rehabilitation, supervised weight restoration and regular physical monitoring. Family-based treatment is often recommended for children and adolescents.
Recovery is possible. Treatment should be respectful, collaborative and adapted to the person’s medical and psychological needs. Medicines may help related depression or anxiety but do not replace eating-disorder treatment.
Supporting someone
Express concern calmly and focus on wellbeing rather than appearance or weight. Encourage professional help and listen without blame. Do not promise secrecy when immediate safety is at risk.
When to seek urgent help
Urgent assessment is needed for fainting, chest pain, severe weakness, confusion, dehydration, repeated vomiting, blood in vomit, a very slow or irregular heartbeat, or inability to eat or drink. Call emergency services if there is collapse, a medical emergency, or immediate risk of suicide or serious self-harm.
Sources
Reviewed: 28 August 2026