Weight loss surgeries are performed to help seriously obese patients lose weight when diet and lifestyle modifications have failed to bring the needed results by themselves. Common types of weight loss surgery, also called bariatric surgery, include traditional gastric bypass, sleeve gastrectomy, adjustable gastric band surgery and biliopancreatic diversion with duodenal switch gastric bypass. The goal of these surgeries is to reduce the amount of food that the stomach can accept and/or to restrict the amount of nutrients that can be absorbed by the body from food. In gastric bypass surgery, also called Roux-en-Y gastric bypass, a small stomach pouch is created to limit the amount of food that can be consumed in each meal and the small intestine is rerouted. This procedure has been shown to precipitate substantial, long-term results including the loss of up to 80 percent of a patient’s excess weight. A sleeve gastrectomy entails the removal of a majority of the stomach to restrict food consumption. Like gastric bypass, this procedure produces an effect on hormones in the gut that helps patients feel less hungry and better control their blood sugar. Results are comparable to those for gastric bypass. Adjustable gastric band surgery involves the placement of an inflatable band around the top portion of the stomach, which helps reduce hunger and calories consumed and causes the loss of up to 50 percent of a patient’s excess weight. Finally, biliopancreatic diversion with duodenal switch surgery creates a small, tubular stomach pouch while also creating a bypass around a significant portion of the small intestine for up to 70 percent excess weight loss.