The mechanisms of weight loss after bariatric surgery.

Studies of lifestyle advice and dietary intervention show that although moderate, clinically significant weight loss is achievable and results in concomitant improvements in comorbidities, it is invariably transient and recidivism is almost universal. Pharmacotherapeutic options do show promise but are currently inadequate to address many obesity-associated comorbidities. Bariatric surgery consistently results in considerable improvement in weight, alongside a remarkable amelioration in comorbid conditions. Here we describe the physiology of energy balance and the putative mechanisms of change in weight set point following bariatric surgical procedures such as Roux-en-Y gastric bypass and adjustable gastric banding.