The digestive process begins in the mouth, where chewing and saliva breakdown food. Digestion continues in the stomach, where food is turned into a liquid called chyme. Chyme next passes into the small intestine. Here, enzymes from the pancreas and liver further digest food. It is also in the small intestine where all nutrients and vitamins are absorbed. Small fingerlike projections lining the small intestine, called villi, enable digested food to enter the bloodstream.
The Roux-en-Y gastric bypass (RYGB) is the most frequently performed weight loss procedure.
During the first part of RYGB, a small pouch is created in the stomach with staples. This step restricts the amount of food the patient can consume to approximately one ounce. The remaining, larger part of the stomach is then separated from the pouch but is not removed.
The second step of this procedure involves dividing the small intestine just below the duodenum, the first section of the small intestine.
Next, the second section of the small intestine, the jejunum, is brought up and is connected to the newly created pouch. The duodenum is then reconnected to the new intestinal limb giving the intestine the Y shape for which the procedure is named. By bypassing the duodenum, absorption of nutrients and calories is prevented, resulting in significant weight loss.
Complications specific to the RYGB include dumping syndrome, hernias, and nutritional deficiencies.