This reduced risk was independent of other factors such as smoking, high blood pressure and high cholesterol, according to the study in the Nov. 3 issue of The Lancet Diabetes & Endocrinology.

"Our results suggest that bariatric surgery may be a highly effective method of preventing the onset of new diabetes in men and women with severe obesity," study author Martin Gulliford, a professor of public health at King's College London, said in a journal news release.

"We need to understand how weight-loss surgery can be used, together with interventions to increase physical activity and promote healthy eating, as part of an overall diabetes prevention strategy," he added.

Being overweight or obese is a major risk factor for diabetes, and up to 3 percent of severely obese people develop diabetes each year, the study authors noted in the news release.

This study included more than 2,100 obese adults without diabetes who underwent weight-loss surgery -- such as gastric bypass or gastric banding -- and the same number of obese adults who did not have weight-loss surgery or other obesity treatments.

The participants were followed for up to seven years (median 2.8 years). The investigators found that those who had weight-loss surgery -- also called "bariatric" surgery -- were 80 percent less likely to develop diabetes than those who did not have the surgery.

In an accompanying commentary, Dr. Jacques Himpens of Saint Pierre University Hospital in Brussels, Belgium, pointed out that while the findings "bring us a step closer to confirming the effect of bariatric surgery on the incidence of [new] Type 2 diabetes, many questions still remain unanswered, and more evidence is needed to convince endocrinologists about the nature of this effect."