Purpose of review: The use of bariatric surgery is increasing at an enormous rate in all countries but the indications for the operation on the basis of metabolic derangements are not clear as only one controlled randomized trial has been performed so far. Thus, it is not clear whether bariatric surgery should be performed on obese patients with long-standing type 2 diabetes or poorly controlled hypertension or hypertriglyceridemia. The mechanism for the immediate improvement in glucose tolerance after gastric bypass is not clear but is being actively investigated.
Recent findings: Gastric bypass appears to enhance glucagon-like peptide-1 production and suppress glucose-dependent insulinotropic polypeptide production. It appears that patients with type 2 diabetes and a greater BMI gain more benefit from the operation.
Summary: Bariatric surgery, particularly gastric bypass, has powerful and usually persistent effects on type 2 diabetes, dyslipidemia, and hypertension but randomized controlled trials with predefined metabolic entry criteria and planned comprehensive follow-up are required.