Weight Loss After Gastric Bypass Surgery

The gastric bypass operation is designed to limit the amount of food you eat. This is done by stapling and dividing the stomach (A) (stomach stapling). The “new stomach”, also called the pouch, is only about 5-10% the size of the “old stomach” and holds less food. The pouch (B) is about the size of a golf ball as opposed to a normal stomach, which is about the size of a football. The pouch is designed to be permanent, although it is reversible. I do not remove any part of the stomach or other tissue while doing the gastric bypass operation.

When food enters the pouch, it must have a way to leave. An opening is made from the pouch to the small intestine (C). This opening is called a stoma and is about the size of a dime. The opening is made small so that food empties slowly and the sensation of being full or satisfied lasts longer. Because the opening leaving the pouch is small, you must cut your food into small pieces and chew it well for food to be able to pass easily.

It is possible to damage the pouch and stoma by overeating. This could result in stretching the pouch and dilating the stoma. If this occurs, your weight loss and long term results will not be as good. I know this may happen, so I initially make the pouch and stoma extra small to compensate for some stretching and dilation. I simply ask you to do your best to take care of your new pouch and stoma.

The gastric bypass procedure I do, a type of intestinal connection created (C & D), is also unique. This is called a Roux-en-Y. The part of the small intestine that is attached to the pouch , does not metabolize refined sugars well. Approximately 50% of people who undergo this operation may have difficulty with foods or liquids high in refined sugar (table sugar). If you are one of those people, after the operation if you consume a large amount of refined sugar (chocolate bar/cheesecake/syrup), you may not feel well for 5-20 minutes. When large amounts of sugar enter the pouch attached to the intestine, a signal goes to the pancreas to secrete insulin. Insulin lowers your blood sugar and this can give patients what is called “dumping syndrome.” Symptoms may include a cold sweat, an ill stomach, and/or possible diarrhea. In general, this is unpleasant and people would not intentionally experience it again. This mechanism assists in keeping patients from consuming large amounts of calorie rich sugar and helps in weight reduction. The normal amount of sugar in what is not considered desserts or snack food will generally not cause these symptoms.

The bottom part of the stomach is not removed (see diagram E) and continues to function. The bottom part of the stomach will secrete the gastric juices as before and they empty into the small intestine to mix with the food and assist in digestion.

The three mechanisms by which patients lose weight after the gastric bypass surgery are:

  1. The pouch is very small and holds only a tiny portion of food.
  2. The size of the opening, called the stoma, allows food to empty only slowly from the pouch.
  3. A large number of patients have the inability to tolerate large amounts of refined sugar.

As mentioned before, this operation has been performed for over 32 years and at present there is no evidence of a higher rate of gastric cancer, but the incidence after 32 years is not known.

     Weight Loss After Gastric Bypass Surgery

Your weight loss begins immediately after the operation. The majority of people will continue to lose weight for approximately 12 months. The amount of weight a patient will lose every month will vary depending upon the height and weight prior to surgery. A reasonable expectation is to expect to lose 50% or more of your excess body weight and many patients will get to within 30-40 pounds of their ideal body weight. In general, the weight loss is complete within 12 months and may plateau unless you institute an exercise program. The percent of weight loss among different patients varies and depends upon a number of factors such as exercise, food choices, and daily calorie requirements.

When people lose large amounts of weight, there are three areas of the body that may have excess skin. These are the tummy, the back of the upper arms, and the thighs. While an exercise program will help tone muscle and assist in reducing the amount of redundant skin, it may not completely solve the problem. The most common area to be affected is the tummy. I recommend that patients wait until their weight loss is complete and should this be a problem, I write the insurance companies for approval to remove the excess skin and perform a tummy tuck. I have had good success in getting approval to perform this procedure in the past. However, it is more difficult to get insurance approval for the upper arm and the thighs, though this is much less frequently a problem.

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