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Roux-en-Y gastric bypass, the most commonly performed bariatric procedure, is both malabsorptive and restrictive. This surgery can result in two-thirds of extra weight loss within two years. The procedure involves stapling the stomach to create a small pouch that holds less food, and then shaping a portion of the small intestine into a “Y.” The “Y” portion of intestine is then connected to the stomach pouch so that when food is being digested it travels directly into the lower part of the small intestine, bypassing the first part of the small intestine (called the duodenum) and the first part of the second section of the small intestine (called the jejunum). Bypassing these sections of the intestine restricts the amount of calories and nutrients that are absorbed into the body.