Guidelines for the nutritional management of anorexia nervosa

Target audience

1. • Psychiatrists, nurses and other mental health professionals involved in the treatment of eating disorders

2. • Adult physicians and paediatricians treating patients with anorexia nervosa

3. • Dietitians

4. • General practitioners

5. • Psychotherapists and counsellors working with eating disorders.

Key features and recommendations

Good nutritional management is essential to the treatment of anorexia nervosa. However, there is relatively little guidance on nutrition available to professionals treating this serious disorder. This report was produced by a multidisciplinary group which included specialists in eating disorders in adults and children, dietitians and experts in clinical nutrition.

Nutrition should always be considered in its psychological context. Patients require comprehensive physical, nutritional and laboratory assessment. Aggressive attempts to drive weight gain early in treatment are potentially dangerous. The first stage of treatment includes correction of hypoglycaemia, electrolyte disturbance and dehydration, and stabilisation of cardiovascular function. The second stage is the correction of nutrient deficiencies and the third is correction of body composition. Biochemical disturbances are common, but measurements of electrolytes in the blood may mask a significant deficit. Electrolyte supplementation is often required and micronutrient supplementation is recommended. Iron supplements may be dangerous during the early stages of treatment.

A weekly weight gain of 0.5-1.0 kg is suggested for in-patients and 0.5 kg for out-patients. The amount of food should be limited at first, and increased slowly. The early stages of refeeding are a high-risk period and close medical monitoring is required. Refeeding can unmask hidden biochemical deficiencies and hypophosphataemia may develop rapidly.

Enteral feeding has a limited role. The use of enteral feeding should be considered carefully as it may be very distressing to the patient. It may be needed as a lifesaving measure, but should be used for the minimum length of time. Enteral feeding requires a clinical team skilled in its use; detailed advice is provided.

Eating disorders services for children and adolescents should be staffed by clinicians experienced in work with this group. Anorexia nervosa can develop without weight loss during a stage of expected growth. Weight loss may be underestimated if calculated on the body mass index (BMI) alone and we recommend the use of BMI centiles up to the age of 20 years. The management plan should always be presented in an age-appropriate manner and the patient’s cooperation should be gained if possible. The involvement of parents is vital.