Gastric bypass and other weight-loss surgeries — known collectively as bariatric surgery — involve making changes to your digestive system to help you lose weight. Bariatric surgery is done when diet and exercise haven't worked or when you have serious health problems because of your weight. Some procedures limit how much you can eat. Other procedures work by reducing the body's ability to absorb nutrients. Some procedures do both.
While bariatric surgery can offer many benefits, all forms of weight-loss surgery are major procedures that can pose serious risks and side effects. Also, you must make permanent healthy changes to your diet and get regular exercise to help ensure the long-term success of bariatric surgery.
What Is Gastric Sleeve Surgery?
Gastric sleeve (also called sleeve gastrectomy) is the most common weight loss procedure. With this operation, the surgeon removes part of the stomach and makes a tube or "sleeve" out of the rest of the stomach. The new, banana-shaped stomach is much smaller than the original stomach. Part of the stomach that's removed makes hormones that increase appetite and help control insulin. So, a person's appetite decreases and insulin resistance improves after gastric sleeve surgery.
After the operation, a person will eat less, feel full sooner, and be less hungry. The gastric sleeve operation only changes the stomach. The gastric sleeve procedure is not reversible.
What Is Gastric Bypass Surgery?
In a gastric bypass (also called "Roux-en-Y" gastric bypass), a surgeon creates a small pouch at the top of the stomach. This pouch becomes the new stomach. Surgeons then connect the pouch to the middle part of the small intestine, bypassing the upper part of the small intestine.
After the surgery, the stomach pouch holds a lot less food than a normal-sized stomach. A person will eat less, feel full sooner, and be less hungry. And fewer calories and nutrients are absorbed because the small intestine is shorter.
People who get gastric bypass tend to lose more weight than people who get the gastric sleeve, but there can be more problems too. The gastric bypass procedure is not reversible.
What Are the Risks of Weight Loss Surgery?
Weight loss surgery, like any surgery, does come with risks. People who've had weight loss surgery may have pain, nausea, vomiting, diarrhea, and acid reflux (heartburn) after eating — especially if they eat too much or too quickly.
Uncommon but more serious problems include:
1. bleeding
2. a bad reaction to anesthesia
3. infection near the cuts used for the surgery
4. a leaky stomach or intestine, which can lead to an infection of the area around the stomach and other organs
5. a blood clot in the legs or lungs
6. blockage in the intestines
7. gastroesophageal reflux
8. vitamin and mineral deficiencies
9. weight regain
"Dumping syndrome" is a problem mainly seen with gastric bypass. This is when food moves too quickly through the stomach and intestines, causing nausea, dizziness, sweating, stomach cramps, and diarrhea. Eating high-sugar or high-fat foods makes dumping worse, so people who have had weight loss surgery need to be careful about what they eat.