Biliopancreatic diversion with duodenal switch. A type of gastric bypass surgery. It is a multipart procedure where about 80 percent of the stomach is removed. The valve that releases food to the small intestine remains, along with a limited portion of the small intestine that normally connects to the stomach (duodenum). The surgery bypasses the majority of the intestine by connecting the end portion of the intestine to the duodenum near the stomach (duodenal switch and biliopancreatic diversion). This surgery both limits how much you can eat and reduces the absorption of nutrients. It’s very effective, but has more risks, including malnutrition and vitamin deficiencies. It’s generally used for people who have a body mass index greater than 50.