Roux-en-Y gastric bypass surgery uses a combination of restriction and malabsorption. During the procedure, the surgeon uses a stapling device to create a small upper stomach pouch that restricts the amount of food you will be able to consume. At the same time the intestines are rerouted so that food bypasses a large part of the stomach and most of the intestine. This shortening of the digestive route delays the mixing of food and digestive juices and reduces caloric intake. In most cases, patients report an early sense of fullness, combined with a sense of satisfaction that reduces the desire to eat.

Gastric bypass patients typically lose between 60 and 80 percent of excess weight in the first year following surgery. Many health problems, such as back pain, sleep apnea, high blood pressure, type 2 diabetes and depression, improve or are resolved following surgery.