- Most common weight loss operation performed in the United States;
- Offers the best weight loss
- Provides restriction and malabsorption
- Requires close follow-up to prevent nutritional deficiencies
The Roux-en-Y gastric bypass operation has been used since the late 1960's to achieve significant weight-loss in people affected by morbid obesity. The operation leads to weight-loss for two different reasons: A small stomach pouch reduces the amount you can eat (restriction) and A small amount of intestine is bypassed so you don't absorb all of the food that you eat (malabsorption).
A gastric bypass can be done through a single long incision (open) or through a series of small incisions (laparoscopic). Regardless of how you choose to have the operation done, the "inside part" is the same.
The surgery involves three basic steps:
- Creation of a small pouch (Proximal Pouch of Stomach)
- Bypassing part of the small intestine (creating the "Short" Intestinal Roux Limb)
- Attaching the bypassed intestine (Roux Limb) to the pouch
The operation can usually be done in two hours or less, but this will depend on many factors. Most patients will need to stay in the hospital for two to three days after their operation and should be ready to return to full activity within two weeks.
To understand how a gastric bypass leads to weight-loss it is helpful to review what you probably learned in grade school: Human Digestion. When we swallow food, it goes down the esophagus and into the stomach. The stomach is able to hold huge amounts of food (think about a hot dog eating contest). The stomach then churns the food and mixes it with digestive juices to break the solid food down into a liquid form. That liquid food then leaves the stomach and goes into the small intestine where it can be absorbed to help fuel our bodies. The small gastric pouch created during the gastric bypass limits the amount of food (calories) a person can eat during a meal. The pouch will initially hold a very small amount of food (about half a shot glass full or one table spoon), however, by one year after surgery, a gastric bypass patient will be able to eat a meal equal in size to what a 7 or 8-year-old child could eat. Although the meals after gastric bypass surgery are much, much smaller than they were before surgery, they still give the individual the same "full" or "satisfied" feeling they used to get with a much larger meal. Until food is broken down into the liquid form, it cannot be absorbed by the small intestine. After a gastric bypass, the food does not turn into liquid until it leaves the "Short Intestinal Roux Limb" (see picture). The "Short Intestinal Roux Limb" therefore does not absorb the food that is eaten which results in less food (calories) being absorbed overall (called malabsorption). This also means vitamins and minerals aren't as well absorbed so gastric bypass patients must be on vitamin and mineral supplements for the remainder of their life. The "Short Intestinal Roux Limb" does not handle sugar or starches well so gastric bypass patients must limit their intake of sugary and starchy foods. If they don't, they may experience something referred to as "The Dumping Syndrome." Usually 10-15 minutes after eating a sugary or starchy food, the individual who is "dumping" begins to experience many of the following symptoms: sweating, flushing skin, rapid heart rate, dizziness, low blood pressure, abdominal pain, vomiting, diarrhea and shakiness. Dumping typically lasts 30-45 minutes long and then will go away. This gives the gastric bypass patient plenty of time to reflect on the food choice that they made that led to the dumping. For many people who have had a gastric bypass, dumping or the fear of dumping helps them make better food choices and stay away from foods that have tempted them in the past.
Weight-loss: After a gastric bypass, one can expect to lose around 70 percent of the extra weight they are carrying. This means if someone were 100 pounds overweight, they would be expected to lose 70 pounds after gastric bypass. This weight-loss occurs throughout the first 12-15 months after surgery. Proper follow-up and participation in a program that stresses lifestyle modification (dietary, behavioral and exercise changes) will improve the chance a gastric bypass patient will maximize their weight-loss and maintain it for a lifetime. As the weight comes off, most will see significant improvement in their health and quality of life. Diabetes, highblood pressure, sleep apnea and reflux disease can virtually disappear with significant weight-loss. Most will find they require fewer and fewer medicines over time.
Complications: The major complications that can occur early on after gastric bypass include bleeding, leakage, infections, bowel blockages, blood clots in the lungs (pulmonary emboli) and death. The chance of dying in the first 30 days after a gastric bypass is around .02-.5 percent. Long-term complications that can occur after a gastric bypass include strictures, ulcers, hernias, weight regain, vitamin and mineral deficiencies and malnutrition. Most of the long-term problems linked to the gastric bypass operation can be prevented with good follow-up.
Conclusion: Gastric bypass is a time-tested, reliable weight-loss operation that can lead to significant and sustained weight-loss by reducing food intake and food absorption. While there are short and long-term risks associated with the surgery, most of these issues can be prevented through close follow-up. As with any weight-loss operation, the best results are achieved when the surgery is combined with a multi-disciplinary program that focuses on lifestyle and behavioral changes.
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