Gastric bypass procedures (GBP) are any of a group of similar operations that first divides the stomach into a small upper pouch and a much larger lower "remnant" pouch and then re-arranges the small intestine to allow both pouches to stay connected to it. Surgeons have developed several different ways to reconnect the intestine, thus leading to several different GBP names. Any GBP leads to a marked reduction in the functional volume of the stomach, accompanied by an altered physiological and physical response to food. The operation is prescribed to treat morbid obesity, defined as a BMI greater than 40, and also to treat type 2 diabetes, hypertension, sleep apnea, and other co-morbid conditions...