What is the new stomach from a gastric bypass made from?

The new stomach created during a gastric bypass is typically formed from the patient's small intestine. The procedure, which is technically known as Roux-en-Y gastric bypass (RYGB), begins with the surgeon creating a small pouch from the upper part of your stomach that separates it from the lower portion. This reduces the size of your stomach, allowing you to feel full after only eating small portions. After that, they connect this new pouch to a section of your small intestine called jejunum, which then serves as your “new” stomach.

This connection or anastomosis flows in one direction meaning food must travel through you entire digestive tract before making its way back up through your newly attached jejunal loop and emptying into the smaller pouch that now serves as your stomach. The result is a faster digestion process and decreased caloric absorption, both leading to successful weight loss in most cases when combined with lifestyle change and proper nutrition education postoperatively.