Gastric bypass surgery decreases the size of the patient's stomach to a small pouch. It is easy to keep the stomach pouch small following surgery, as the stomach simply cannot handle much. Over time though, the patient may begin eating things that stretch it out. To return it to its smaller size the diet must be modified.
Surgery
Bariatric surgery has become a common procedure where the surgeons mechanically shrink the stomach of a patient. The procedure is done by stapling the stomach, making the portion that holds food about the size of a shot glass. In some cases part of the small intestine, which absorbs nutrients, is bypassed, resulting in more rapid weight loss. Another popular form of the procedure is to band the stomach so it will only hold a small amount of food before the person feels full.
Shrinkage
Some patients do return to their bad eating habits after surgery when the stomach calms down. By eating too much of the wrong foods the tiny pouch can be stretched somewhat. To shrink a stomach pouch post-surgery that has been stretched due to eating inappropriately, simply return to the initial diet you were on immediately following surgery. The meal replacement shakes will provide you with all the needed nutrition in a very small size. After several weeks of this diet the stomach returns to its post-surgery size. Returning to inappropriate eating habits will stretch it out again, though.
Eating less of inappropriate foods will also shrink the stomach pouch some, though not as much as returning to the immediate post-op diet. However, eating less will reinforce good eating habits and should be a part of a long-term plan to keep the stomach pouch small, which was the whole point of the surgery.
The Diet
For the first several weeks following surgery the Duke Medical Center recommends an all-liquid diet to accommodate the now-smaller stomach pouch, with the following considerations. Since most of our fluid is consumed in the food we eat, and bariatric patients are no longer eating very much, it is recommended to drink large amounts of a low- or no-calorie beverage, such as Propel water or Crystal Light. The other part of the initial diet is to ensure the patient consumes adequate nutrients, including vitamins, minerals and protein. A meal replacement drink such as Ensure should be consumed in small frequent amounts throughout the day. The ideal composition of the meal replacement shake is to have low sugar and high protein, providing the body with the building blocks it needs for cell repair.