Insulin resistance in bariatric surgery

Purpose of review To give an updated review on the underlying mechanisms and clinical effects of improved glucose control after bariatric surgery. Recent findings The basic principles of the mechanism for the metabolic effects of bariatric surgery can be categorized into calorie restriction, deviation of nutrients, and reduced amounts of adipose tissue. Recent findings suggest the importance of early changes following deviation of nutrients to more distal parts of the small bowel resulting in altered release of gastrointestinal hormones, altered gut microbiota, and weight-reduction. In the long-term, loss of adipose tissue results in reduced inflammation and improved insulin sensitivity. From a clinical perspective these changes are associated with remission of diabetes in patients with morbid obesity and type 2 diabetes, prevention of diabetes in patients with insulin resistance without overt type 2 diabetes and prevention of both microvascular and macrovascular complications for all patients with morbid obesity. At present, bariatric surgery remains the most effective treatment option to improve glucose control and long-term complications associated with hyperglycemia in patients with obesity. Although the mechanisms behind these metabolic effects remain only partially understood, further knowledge on these complex mechanisms may help identifying durable treatment options for morbid obesity and important metabolic comorbidities.