The duodenal switch (also referred to as biliopancreatic diversion with duodenal switch or “switch”) involves two bariatric techniques in one operation: a vertical gastric sleeve attached to a distal intestinal roux-en-Y bypass. During this operation, approximately 80% of the stomach is removed. The switch procedure is a well established bariatric operation with excellent long term weight loss (on average 80%) and a track record as the most effective metabolic operation for treating diabetes mellitus (91%). The effectiveness of the procedure is based on a combination of restriction, fat malabsorption, and hormonal effects that reduce hunger, increase satiety, and decrease insulin resistance. The operation is more technically challenging but still performed laparoscopically. Generally, we reserve this approach for patients with higher BMI or insulin dependent diabetics. Patients need to expect some higher risk of both short and long term complications, including leakage, infection, malnutrition, and diarrhea. Your doctor can help you decide which approach best fits your needs.