Procedures altering gastro-intesinal peptides with gastric restriction
Roux-en-y Bypass or gastric bypass

The Roux-en-Y is currently the most extensively performed bariatric procedure. It can be accomplished either open or laparoscopically, the preferred method being laparoscopic. This operation is the most common of malabsorptive and restrictive surgical procedures. In the Roux-en-Y, a small stomach pouch is created to restrict food intake.
The intestine is severed, the lower section of the small intestine is attached to the pouch to allow food to bypass the remaining stomach, duodenum (the first segment of the small intestine), and the first portion of the jejunum (the second segment of the small intestine). Roux-en-Y’s are done either proximal (with a shorter length of the intestines bypassed), or distal (with more of the intestines bypassed).
Gastric bypass surgery will induce weight loss by one of three mechanisms:
1. Restriction of volume
2 . 120 – 150cm of the gastric outlet is bypassed, resulting in minor calorie wasting