BMI 35 with comorbidity or 40 without is the classic threshold — but metabolic disease lowers it, and guidelines have moved.
BMI ≥40, or ≥35 with an obesity-related condition such as type-2 diabetes, sleep apnoea, hypertension or severe joint disease. These have guided practice for decades and still frame most insurance criteria.
Major bariatric societies now support surgery from BMI 30–35 in patients with type-2 diabetes that is not controlled by medication, because metabolic benefit does not track body weight alone.
Uncontrolled diabetes, severe sleep apnoea, non-alcoholic fatty liver disease and a documented history of failed supervised weight loss all strengthen the case at a lower BMI.
Untreated eating disorders, active substance dependence, unmanaged severe psychiatric illness and inability to attend follow-up. These are not moral judgements — each one predicts poor outcomes and is addressed before, not instead of, surgery.
No. Waist circumference, body composition, comorbidities and previous weight-loss attempts all form part of the assessment.