I had the Ruen-Y type of Gastric Bypass in  November 2005 & wieghed 507LBS

The stomach is divided to create a small pouch that can hold approximately 30cc (1/8 cup) from its original capacity of 2000 - 3000cc. This dramatically limits the amount of food that can be eaten. The remaining stomach is stapled closed and surgically separated but not removed.

The small intestine is divided further downstream and attached to the new pouch so that any food eaten bypasses the old stomach. The connection from your new stomach to the intestine is small, approximately 1.0-1.5 cm wide (approximately 1/2 inch) to limit the food that passes through.

The stomach and the duodenum (the first section of small intestine) continue to produce and receive liver bile, enzymes and pancreatic juice needed for digestion. This bowel is then rejoined to the side of the jejunum, the second part of the intestine to form a common limb. This opening is wide so food can pass through easily. Pancreatic juices and liver bile from the duodenum now reaches the food as it travels down the jejunum. Liver bile begins fat absorption at this time. Fat is only being partially absorbed. Sugars are absorbed but discouraged because they cause most patients to experience the "dumping syndrome". This is a very uncomfortable feeling of flushing, cold sweats, palpitations, weakness and abdominal cramps.

What is Gastric Bypass?