Gastric bypass surgery has been reportedly considered one of the most effective ways to treat type 2 diabetes in obese people. But a recent study questioned if the procedure truly has a unique metabolic effect in diabetics, or if is weight loss after the surgery that really causes the beneficial effects in people.
“It has been presumed that gastric bypass surgery has therapeutic, metabolic effects that result in better glucose control and even remission of diabetes beyond the effects expected from weight loss alone,” principal investigator Dr. Samuel Klein, director of Washington University’s Center for Human Nutrition, stated in the news release provided to Fox News.
However, Klein’s team of researchers from Washington University School of Medicine in St. Louis found in their recent study that it is not necessarily the surgery itself that drives metabolic improvements, including remission of diabetes, but rather the weight loss after surgery that creates this effect, according to the news release.
“We found gastric bypass surgery improves metabolic function by causing weight loss. There were no differences in the reduction of diabetes medications or in the rate of diabetes remission between surgery patients and those who lost equivalent amounts of weight through diet alone.”
The research, published this week in The New England Journal of Medicine, said the team of researchers compared 11 severely obese patients with diabetes who had the gastric bypass surgery to 11 severely obese diabetic patients who lost the same percentage — 18 percent — of their body weight through diet alone.
The members of both groups had similar metabolic improvements throughout the course of the day, including improved insulin action in the liver, fat and muscle tissue, lower blood sugar levels, and less need for insulin and other diabetes medications, per the release. Since the group who lost weight strictly through diet did just as well as the surgical group, the researchers concluded the improvements were due to weight loss, rather than from physiological changes caused by the surgery itself.
“It has been suggested that weight loss induced by gastric bypass surgery is different from weight loss induced by a low-calorie diet, based on the fact that certain factors — such as increased bile acid concentrations, decreased branched-chain amino acid concentrations and alterations in the gut microbiome — are different in surgery patients and may be responsible for the unique therapeutic effects of gastric bypass surgery,” Klein said in the news release.
Although those factors were different after weight loss in the surgical patients compared to the non-surgical patients, “those changes were not associated with any physiologically or clinically important metabolic benefits,” the study's lead author said in the release.
Klein, however, did raise the issue that “losing 18 percent of body weight with diet therapy alone is extraordinarily difficult and unrealistic for most people with obesity.”
“In contrast, gastric bypass surgery leads to marked and sustained long-term weight loss, which makes it a potent therapy for people with diabetes," Klein, the chief of the Division of Geriatrics and Nutritional Science, added.