The many types of baratric surgery procedures may be divided into two categories, restrictive and malabsorptive. Restrictive techniques limit the amount of food the stomach can hold. Malabsorptive techniques remove part of the digestive system limiting the amount of calories absorbed by the body, such as a gastric bypass. In banding techniques, a synthetic band is placed near the top of the stomach to section off a pouch. In comparison, the Roux-en-Y, duodenal switch, and gastric sleeve use staples to reduce the size of the stomach. In a biliopancreatic diversion a portion of the stomach is removed.