Gastric bypass surgery is an operation that creates a small pouch to restrict food intake and bypasses a segment of the small intestine. In the gastric bypass procedure, a surgeon makes a direct connection from the stomach pouch to a lower segment of the small intestine, bypassing the duodenum (the first part of the small intestine) and some of the jejunum (the second part of the small intestine), delaying the mixing of ingested food and the digestive enzymes.

Roux-en-Y gastric bypass is the most common type of bariatric surgery. The surgeon begins by creating a small pouch by dividing the upper end of the stomach. This restricts the food intake. Next, a section of the small intestine is attached to the pouch to allow food to bypass the duodenum, as well as the first portion of the jejunum. The small intestine is re-connected 150 centimeters from the pouch to allow ingested food and digestive enzymes to mix.

Watch our animated video on how the procedure works.