What are the key diagnostic criteria for anorexia nervosa and bulimia nervosa according to NICE guidelines?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Key diagnostic criteria for anorexia nervosa according to NICE guidelines include:

  • Unusually low body mass index (BMI) or body weight for age, often with rapid weight loss.
  • Dieting or restrictive eating practices that cause concern to the individual, family, carers, or professionals.
  • A disproportionate concern about weight or shape, including fear of weight gain.
  • Physical signs of malnutrition such as poor circulation, dizziness, palpitations, fainting, or pallor.
  • Menstrual or other endocrine disturbances, or unexplained gastrointestinal symptoms.
  • Compensatory behaviours such as vomiting, laxative or diuretic misuse, or excessive exercise.
  • Social withdrawal, particularly from food-related situations.
  • In children and young people, faltering growth or delayed puberty may also be present.

Key diagnostic criteria for bulimia nervosa according to NICE guidelines include:

  • Recurrent episodes of binge eating characterized by eating an excessive amount of food in a discrete period and a sense of lack of control over eating during the episode.
  • Recurrent inappropriate compensatory behaviours to prevent weight gain, such as self-induced vomiting, misuse of laxatives, diuretics, or other medications, fasting, or excessive exercise.
  • The binge eating and compensatory behaviours both occur, on average, at least once a week for three months.
  • A self-evaluation that is unduly influenced by body shape and weight.

These criteria are used to identify suspected cases and guide referral to specialist eating disorder services for further assessment and treatment ,.

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