Gastric bypass procedures have increased in regularity recently, due mainly to the growing number of incidences of obesity in the US. There are two main methodological variants within gastric bypass surgery today, the original ‘loop’ method, pioneered in the 1960s having been largely abandoned. Presently, the most commonly used method in gastric bypass surgery is the Proximal, or Roux en-Y system.
After Proximal, or Roux en-Y gastric bypass surgery, the amount of food which can be eaten by a patient is severely restricted because, after swallowed, it moves into a small upper gastric (stomach) pouch, separated from the remainder of the stomach in surgery. From here, food then moves gradually into a ‘Roux limb’ of small bowel formed in surgery, bypassing the rest of the stomach and the initial part of the small intestine. This causes the patient to absorb fewer calories.
The other main form of gastric bypass surgery is the biliopancreatic diversion. This is a more complicated and less typically carried-out procedure. In its being carried out, portions of the patient’s stomach are literally removed. The small pouch of the patient’s stomach remaining is then directly connected to the end section of the small bowel, thus bypassing the rest of the intestine and, again, reducing calorie intake by the patient. Whilst this more drastic procedure is more regularly successful in facilitating weight loss, it is not nearly so widely carried out. This is because it carries with it a high risk of introducing inadvertent deficiencies to the digestive system.