Gastric bypass surgery refers to a surgical process in which the stomach is divided into a small upper pouch and a much larger lower “remnant” pouch and then the small intestine is rearranged to connect to both. Gastric bypass, also called Roux-en-Y (roo-en-wy) gastric bypass, is a type of weight-loss surgery that involves creating a small pouch from the stomach and connecting the newly created pouch directly to the small intestine. After gastric bypass, swallowed food will go into this small pouch of stomach and then directly into the small intestine, thereby bypassing most of your stomach and the first section of your small intestine. Why it’s done Gastric bypass is done to help you lose excess weight and reduce your risk of potentially life-threatening weight-related health problems, including: Gastroesophageal reflux disease Heart disease High blood pressure High cholesterol Obstructive sleep apnea Type 2 diabetes Stroke Infertility