Bariatric surgery is an option for people who are morbidly obese—those who have a body mass index (BMI) of 40 or greater or who are more than 80 pounds overweight (women) or 100 pounds overweight (men)—and have been unable to lose weight through diet, exercise and medication. Surgery may also be considered for people with a BMI between 35 and 40 who have serious obesity-related complications such as diabetes, high blood pressure or high triglycerides.
Approximately 179,000 Americans underwent a bariatric surgery procedure in 2013 (the most recent year for which statistics are available, according to the American Society for Metabolic and Bariatric Surgery (ABMS). Bariatric surgery does not remove fat tissue. Instead, it usually involves reducing the size of the stomach and/or the body’s ability to absorb nutrients from food.
Research suggests that bariatric surgery can have a significant impact on health. One report reviewed 136 studies with more than 22,000 patients who underwent surgery. Two years after surgery, the patients had lost an average of 61 percent of their excess weight. They also experienced significant improvements in diabetes, high blood pressure and cholesterol levels. Those and other results are encouraging, but whether these improvements will reduce the risk of heart attacks, strokes or death or will be maintained for longer than a decade is not known.
At least 10 percent of people who undergo bariatric surgery experience unsatisfactory weight loss or regain much of the weight they lost.
Bariatric surgery is generally safe, but as with any surgical procedure there’s a risk of serious complications and possibly death. These risks are higher in people with a BMI above 50 (“super obese”), in those with other health problems such as high blood pressure or diabetes, and in individuals over age 45. Common complications of bariatric surgery include dumping syndrome (vomiting, reflux and diarrhea), leaks or narrowing at the site where the intestine is joined to the stomach, and abdominal hernias. In general, the risk of death is small—less than 1 percent if the procedure is performed at an academic medical center that does a large number of bariatric surgeries.
The three common types of bariatric procedures are vertical banded gastroplasty, laparoscopic adjustable gastric banding and gastric bypass. Most bariatric operations are performed using laparoscopy, in which surgical instruments are inserted through small incisions in the abdominal wall. Gastric bypass is the most commonly recommended procedure, but your surgeon will help you decide which procedure is best for you (often this is dictated by the preference and experience of the surgeon performing the operation).
1. Vertical banded gastroplasty
This operation (also called gastric partitioning) divides the stomach into two sections. A stapling instrument is used to section off a golf ball-sized pouch at the top of the stomach. Then, an inflexible ring (band) is put in place to encircle the small opening between the pouch and the rest of the stomach. This procedure allows small amounts of food to pass from the pouch to the remaining portion of the stomach. The likelihood of overeating is reduced, because a small quantity of food creates feelings of fullness.
Several studies show that vertical banded gastroplasty results in significant weight loss and improves obesity-related complications. However, you must be willing to eat smaller portions of food and to chew your food well and slowly to prevent nausea and vomiting as well as overstretching the stomach. Complications of the procedure include deterioration of the band or staple line. The risk of infection or death from complications is less than 1 percent.
Vertical banded gastroplasty can be done using laparoscopy. You may want to find a surgeon who has experience with this approach, because it is associated with a speedier recovery.
2. Laparoscopic adjustable gastric banding
This gastric restriction procedure sections off a portion of the stomach without stapling. Using minimally invasive laparoscopic techniques, an adjustable, hollow, silicone band (called a lap-band) is wrapped around the upper part of the stomach to create a small pouch. Attached to the band is a flexible tube connected to a miniature access port, implanted just beneath the skin of the abdomen. Through the access port, the physician can remove or add saline solution to the band to adjust its fit around the stomach and change the size of the narrow passage that connects the pouch to the lower stomach.
Laparoscopic gastric banding is reversible but is somewhat less effective than vertical banded gastroplasty and gastric bypass. It is most useful for people with moderate obesity. In 2011, its use was expanded to include obese individuals with a BMI of 30 to 34 who have an existing condition related to their obesity.
While the procedure is generally considered safe, the band has to be removed in about one-quarter of people because of nausea, vomiting, heartburn, abdominal pain, or band slippage.
3. Gastric bypass
This procedure is done in combination with gastric restriction. The size of the stomach is first reduced by using staples to create a small upper gastric pouch that is completely separated from the rest of the stomach. The small pouch decreases the quantity of food an individual can comfortably consume. Then a segment of the small intestine is surgically rerouted to connect directly to this gastric pouch.
This procedure allows ingested food to bypass the majority of the stomach as well as part of the small intestine. Since nutrient absorption takes place in the small intestine, the number of calories available to the body is reduced by limiting both the amount of time food spends there and the amount of small intestine exposed to—and thus available to absorb—food.
The risks associated with gastric bypass are similar to those of vertical banded gastroplasty. However, approximately 30 percent of bypass patients also develop deficiencies of nutrients that are normally absorbed in the small intestine. Consequently, it’s necessary to take a daily multivitamin-mineral supplement.
Gastric bypass is effective for initiating and maintaining weight loss. In one study, people who had gastric bypass tended to lose more weight over the course of a year than those who had vertical banded gastroplasty. In a recent study comparing gastric bypass to banding, researchers found that after a year, the bypass procedure offered greater weight loss and resolution of diabetes, a similar rate of complications and a lower rate of reoperations. Gastric bypass is best for patients with the highest BMIs.