Metabolic and nutritional changes after bariatric surgery.

Bariatric surgery is the most durable intervention for severe obesity. Appropriate candidates for surgery include those with a body mass index over 40 kg/m(2), or those with a BMI over 35 kg/m(2) who also have weight-related comorbidities. Bariatric procedures are categorized as restrictive, where food intake is limited by a small gastric 'pouch'; malabsorptive, where the length of intestine available for nutrient absorption is decreased; or a combination of both.