The Roux-en-Y (hereafter refered to as "RNY") [[Gastric Bypass]] creates a small pouch out of the uppermost part of the stomach, but it also bypasses part of the small intestine. This causes the patient to eat less and also to absorb less of the food eaten, thereby reducing caloric intake. Since the body is not getting everything out of the food, including some nutrients, the patient may need regular screenings to determine what additional vitamins and supplements may be needed to prevent malnutrition and/or anemia. Patients generally see more weight loss with this procedure than with the LAP Band, but it has greater potential for complications.