From Scientific American:
More than 30 million of the Americans classified as obese or extremely obese might benefit from surgery that reconstructs the stomach to accommodate less food. A new study shows that gastric bypass surgery, which leads to weight loss and improvement of related health problems, may yield long-term health benefits. Earlier research had shown improvements but most patients were tracked for shorter intervals. A report published online September 18 in JAMA, Journal of the American Medical Association tracked hundreds of extremely obese patients for six years (body mass index (BMI) above 40 or greater than 35 with health complications) and found that even after this lengthy period of time, those who received the surgery had significantly better health outcomes than those who did not. Preexisting type-2 diabetes went into remission more than half of the time (62 percent of cases). Researchers were unsure if gastric bypass, in which the stomach is reattached farther down on the digestive tract allowing for less food absorption would lead to better long-term health without other interventions, such as dietary or exercise assistance. For the study, the researchers enrolled 835 extremely obese patients who were seeking a from of gastric bypass known as Roux-en-Y. About half of those patients ended up getting the procedure. As an additional control group, the researchers enrolled 321 extremely obese people from the community who were not trying to get the surgery.
Following up with the participants two years later, the researchers found dramatic results. Those who had the surgery experienced a roughly 35 percent weight reduction—for many as much as 100 pounds or more under their baseline weight—whereas the control groups remained extremely obese. Even after six years and without other interventions, the patients who had the surgery were still about 28 percent lighter on average than before and experienced improved quality of life scores compared to the control groups. Stunningly, the procedure lead to at least an 80 percent reduction in the risk of developing type-2 diabetes and a 20-times larger chance that existing diabetes would go into remission. It also lowered risks for cardiovascular disease and hypertension. Those without surgery had increased risk for all of these conditions after six years.