For severely obese, it’s the weight loss alone that drives improvements such as remission of diabetes.
Gastric bypass surgery is the most effective therapy to treat or reverse type 2 diabetes in severely obese patients. Many achieve remission of diabetes following surgery and no longer require diabetes medications. This observation has led to the theory that gastric bypass surgery has unique, weight loss-independent effects in treating diabetes, but this has remained a longstanding question in the field. Now, new research from Washington University School of Medicine in St. Louis indicates that weight loss after surgery, rather than the surgery itself, drives metabolic improvements, such as the remission of diabetes.
The researchers studied severely obese patients with diabetes who had gastric bypass surgery and then lost 18% of their body weight. In a patient who weighs 250 pounds, for example, that would be 45 pounds. The investigators compared those patients with others who also were severely obese with diabetes but had lost the same percentage of body weight through diet alone.
After reaching their weight-loss goals, members of both groups experienced similar improvements in metabolism — such as lower blood sugar levels throughout the day, better insulin action in the liver, muscle and fat tissue, and reductions in the need for insulin and other diabetes medications. Since the group that lost weight through diet alone did just as well as the surgery group, the researchers concluded the improvements were due to weight loss alone, rather than to any physiological changes that resulted from the surgery itself.
The study is published August 20 in The New England Journal of Medicine.
“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,” said principal investigator Samuel Klein, MD, director of Washington University’s Center for Human Nutrition. “But 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.”
More than 40% of adult Americans are obese, and close to one in 10 is severely obese. Each year more than 250,000 people in the U.S. undergo bariatric surgery to help them lose weight….