Type 2 diabetes has long been thought of as a chronic, irreversible disease. Some 25 million Americans are afflicted with the illness, which is associated with obesity and a sedentary lifestyle, as well as high blood pressure. Recent research demonstrated that gastric bypass surgery—a form of bariatric surgery that reduces the size of the stomach—can lead to at least temporary remission of type 2 diabetes in up to 62 percent of extremely obese adults. But can less drastic measures also help some people fight back the progressive disease?

A new randomized controlled trial found that intensive weight loss programs can also increase the odds that overweight adults with type 2 diabetes will see at least partial remission. The findings were published online December 18 in JAMA, The Journal of the American Medical Association. "The increasing worldwide prevalence of type 2 diabetes, along with its wide-ranging complications, has led to hopes that the disease can be reversed or prevented," wrote the authors of the new paper, led by Edward Gregg of the Centers for Disease Control and Prevention.

The study tracked 4,503 overweight adults with type 2 diabetes for four years. About half of the subjects received basic diabetes support and education (including three sessions per year that covered diet, physical activity and support). The other half received more intensive lifestyle-intervention assistance. This second group received weekly individual and group counseling for six months, followed by three-sessions each month for the next six months, and refresher group sessions and individual contact for the subsequent three years. The interventions aimed to help individuals limit daily calories to 1,200 to 1,800—in particular by reducing saturated fat intake—and to help them get the recommended 175 minutes per week of physical activity.

After two years about one in 11 adults in the intervention group experienced at least partial remission of their diabetes, meaning that a patient's blood sugar levels reverted to below diabetes diagnosis levels without medication. Only about one in 60 in the control group, which received only basic support and education, saw any remission after two years. The findings suggest that "partial remission, defined by a transition to prediabetic or normal glucose levels without drug treatment for a specific period, is an obtainable goal for some patients with type 2 diabetes," the researchers noted.

The improvement, however, was not indefinite for everyone. After four years, only about one in 30 people in the intervention group were still seeing an improvement in their condition. Researchers think that regaining weight and falling behind on diet and physical activity goals increase the risk that people will return to a diabetic state.

About one in 75 in the intervention group saw complete remission of their diabetes, in which glucose levels returned to normal without medication.

The study did not find, however, that individuals in the lifestyle intervention group had lower risks for heart trouble, stroke or death than did those in the control group. "This recently led the National Institutes of Health to halt the [trial]," noted David Arterburn, of Group Health Research Institute in Seattle, and Patrick O'Connor, of HealthPartners Institute for Education and Research in Minneapolis, in an essay in the same issue of JAMA. Similar results have come out of studies looking at more intensive medical treatment of diabetes. "A more potent intervention—bariatric surgery—already appears to achieve what intensive medical and lifestyle interventions cannot: reducing cardiovascular events and mortality rates among severely obese patients with type 2 diabetes," they noted.

As with any disease, however, prevention is the best strategy. "The disappointing results of recent trials of intensive lifestyle and medical management in patients with existing type 2 diabetes also underscore the need to more aggressively pursue primary prevention of diabetes," Arterburn and O'Connor noted. One recent study found that compared with no treatment at all, lifestyle interventions reduced the onset of type 2 diabetes by 58 percent in people with pre-diabetes (and the medication metformin reduced the onset rate by 31 percent). Bariatric surgery seemed to reduce the onset of diabetes in obese patients by 83 percent, Arterburn and O'Connor pointed out in their essay.

For people who already have diabetes, however, those who are still in the early stages and those with the biggest weight loss and/or fitness improvement had the best odds for beating the disease. And even if lifestyle interventions aren't capable of dialing back the disease entirely, any reduction—whether through lifestyle or other changes–in the need for medication and in medical complications due to diabetes can be considered an improvement in managing the disease, which already costs the U.S. health system $116 billion each year and is estimated to affect 50 million Americans by 2050.