Obesity is defined as a body mass index (BMI) of 30 kg per m2 or more. It is a risk factor for comorbidities such as type 2 diabetes, coronary heart disease and hypertension. Weight loss reduces the risks of comorbidities and improves long-term survival.
Obesity is managed by dietary advice, exercise, lifestyle changes and medication. Bariatric surgery is considered as a treatment option in selected patients whose BMI is over 40 kg per m2, or over 35 kg per m2 for patients with other significant comorbidities, if they have not lost enough weight using non‑surgical measures.
Surgical procedures aim to help patients lose weight by restricting the size of the stomach (for example, gastric banding or sleeve gastrectomy) and/or by decreasing the patient's capacity to absorb food (for example, Roux-en-Y gastric bypass or biliopancreatic diversion).