Four types of bariatric surgery operations are commonly offered in the United States: adjustable gastric band (AGB), Roux-en-Y gastric bypass (RYGB), biliopancreatic diversion with a duodenal switch (BPD-DS) and vertical sleeve gastrectomy (VSG).
Credit: Walter Pories, M.D. FACS / NIH.
Bariatric surgery is a surgical operation on the stomach and intestine used to treat obesity. It is an option for people who are still severely obese after attempting to lose weight through other methods, such as diet and exercise, or who have a serious health condition related to their obesity, such as Type 2 diabetes.
Weight-loss surgery: How it works
Bariatric surgery makes the stomach smaller — either by restricting the size of the stomach with a band, or physically removing a portion of the stomach with surgery. A smaller stomach means patients eat less, which leads to weight loss. Some types of bariatric surgery also reduce the absorption of food by the body, which also contributes to weight loss. And studies show that some producers cause a change in the level of the hormone that regulates appetite, making people feel less hungry.
Patients can lose up to 80 percent of their excess weight in one to four years after surgery, and many have an easier time keeping it off than they did through dieting, Dr. Sunil Bhoyrul, a weight-loss surgeon in La Jolla, Calif., told Live Science in a 2011 interview. However, up to a third can end up back at their pre-surgical weight seven to 10 years later, Bhoyru said.
The best outcomes occur in people who eat a healthy diet and engage in regular exercise after surgery, according to the National Institute of Diabetes and Digestive Kidney Diseases (NIDDK).
Who's eligible for surgery?
People are eligible for bariatric surgery if they have a body mass index (BMI) of 40 or more, or if they have a serious health problem related to their obesity and have a BMI of 35 or more, according to the NIDDK. People with a BMI of 30 or more are eligible for an adjustable gastric band (one type of bariatric surgery) if they also have at least one health problem linked with obesity.
Anyone thinking about having this surgery should understand the possible risks and benefits of the procedure, and how their life may change afterwards, the NIDDK says.
Types of surgery
There are four main types of bariatric surgery offered in the United States: adjustable gastric band, Roux-en-Y gastric bypass, biliopancreatic diversion with a duodenal switch, and vertical sleeve gastrectomy.
An adjustable gastric band (AGB) is a band that's placed around the top of the stomach, which limits food intake.
Roux-en-Y gastric bypass (RYGB) creates a small pouch out of the top of the stomach, and connects it to part of the small intestine called the jejunum. In this way, food bypasses part of the stomach and the duodenum — the first part of the small intestine.
Biliopancreatic diversion with a duodenal switch (BPD-DS) removes a large portion of the stomach, but leaves a short part of the duodenum, which is then connected to the lower part of the small intestine. This procedure limits the amount of food, vitamins and minerals that are absorbed, which can help with weight loss, but can also increase the risk for long-term problems such as anemia or osteoporosis, the NIDDK says.
A vertical sleeve gastrectomy (VSG) removes most of the stomach (80 to 85 percent), and this smaller stomach limits the amount of food eaten.
Most surgeries done today are laparoscopic, meaning that doctors make small cuts in the belly to insert surgical tools, and use a camera to guide the surgery (as opposed to making one large cut to open up the belly, which is referred to as "open" surgery.)
According to the NIDDK, risks of the surgical procedure include: infection, bleeding, leaks from the places where the intestines are sewn together, and blood clots that can move to the lungs and heart.
Poor absorption of nutrients is also a risk, and patients often need to take vitamins and minerals. If not addressed, lack of certain vitamins can lead to diseases, including pellagra (caused by lack of Vitamin B3/niacin) and beri beri (caused by lack of vitamin B1/thiamine.)
There is also a risk that the gastric band will slip partly out of place, or erode through the stomach, in which case it will need to be removed, according to the National Institute of Health.
Recent studies also suggest that weight loss surgery can increase the risk of alcohol abuse. Although the reason for this risk is not known, some researchers say the surgery increases a person's sensitivity to alcohol.
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