Seed | Eating Disorder Support Service

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helping people not the eating disorder

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What do we mean by a BMI? (Body Mass Index)

  • BMI is a (ratio of weight/height) proxy measure of medical risk in anorexia
  • But they are inadequate as a standalone markers
  • BMI is not critical with regards to risks associated with fluids and electrolytes
  • The recommendations are that a BMI calculation should be combined with an examination of:- Muscle strength, blood pressure, pulse rate, peripheral circulations and core temperature

BMI must not be a stand alone assessment.

  • A BMI does not take into account whether a person is a male or female.
  • Neither does it account for a person's age criteria.
  • Whilst BMI is an indication to what level an adult may be at in their illness (mild, moderate, severe, critical or life threatening) it would perhaps better to use a child centile growth chart as a more accurate assessment in the case of a younger person.

BMI - South London and Maudsley Eating Disorder Clinic Guidelines:

  • 20.0 - 18.5 Normal 'Healthy' Weight
  • 18.5 - 17.5 Underweight
  • 17.5 - 15> Anorexia Nervosa
  • 15.0 - 13.5 Severe Anorexia
  • 13.5 - 12.0 Critical Anx: Organs fail
  • <12 Life Threatening

What is meant by 'what level' is a person at with their Eating Disorder?

Mild Anorexia/Bulimia

GP oversight, counselling, self help. Still managing to continue with day to day activities

Moderate Anorexia/Bulimia

GP oversight, self help, counselling, maybe CBT (Cognitive Behavioral Therapy) - continuing to respond well to therapy and still able to attend school or place of work.

Severe Anorexia/Bulimia

Closer monitoring by the GP, psychology/psychiatry, self help.


Close GP involvement, Hospitalisation in a general ward, a psychiatric unit or in-patient in a specialised eating disorder unit.

Life Threatening

Hospitalisation in a General Hospital/Tube Feed.