According to Dr. Edward Eaton Mason - the father of bariatric surgery - the common misunderstanding of gastric bypass surgery is that "the pouch" causes weight loss because it is so small and therefore the patient eats less. Although that principal holds true for the first six months following surgery, Dr. Mason asserts that it is not why the pouch actually works to assist the patient in weight loss long term.

Let's first understand that "the pouch" is formed as part of the stomach is used to create a small pouch, which is separated from the rest of the stomach and connected directly to the small intestine. Food enters the small stomach pouch then exits directly into the intestines, bypassing the normal caloric absorption process. This is a simplified explanation of gastric bypass and suffices for the purpose of this sharepost.

Through his research, Dr. Mason found there is regular growth of the pouch, which is about the size of an egg, for two-years after surgery on average. After the second year, pouches stop growing and end at 6-10 oz. capacity.

Dr. Mason compared the weight loss of people relative to their pouch size in order to determine if the size of the pouch made a difference in the amount of weight lost. His findings showed no difference in the percentage of weight lost, and prove it is not the size of the pouch -- but rather how it is used -- that makes weight-loss maintenance possible.

The truth is that pouch is a tool that patients must learn to use so as to get the "satisfied" feeling of being full to last long enough until the next meal.

The following are clinical observations how the pouch works:

1. Success requires that a small pouch is created with a small outlet. Using the thick, hard to stretch part of the stomach in making the pouch is important.

2. Almost all patients always feel full 24/7 for the first months, then that feeling disappears.

3. Getting a sense of "fullness" with each meal is essential to success. Avoid grazing.

4. Regular meals larger than 1 ½ cups (12 oz) will result in eventual weight gain.

5. Lightly stretching the pouch with each meal sends a signal to the brain that the body doesn't need any more food.

6. Maintaining the sense of fullness requires keeping the pouch stretched for a while.

7. Incredible hunger will develop if there is no food or drink for eight hours (fasting).

8. ‘Soft foods' empty from the pouch quickly. ‘Heavy' foods empty more slowly and thus make the feeling of fullness last longer. By eating "soft foods" patients will get hungry too soon and be hungry before their next meal, which can cause snacking, thus poor weight loss or weight regain.

9. Meat and slightly cooked or raw vegetables are good for you and empty very slowly from the pouch.

10. By drinking water as much as possible as fast as possible before a meal ("water loading"), the patient will get a feeling of fullness that lasts 15-25 minutes.