Hundreds of overweight or obese people with diabetes have been able to do something very few Americans have done: lose a big chunk of weight and keep it off for 10 years.
So should it matter if that epic weight loss didn't reduce the risk of heart disease? Maybe not.
That's one response to the results of the Look AHEAD clinical trial, which checked to see if losing weight reduced heart disease risk in people with Type 2 diabetes.
Maintaining a healthful weight is an important way to prevent and manage diabetes. It's also helps reduce heart disease risk. So the researchers were surprised to find that even though the study participants lost weight and kept it off, they didn't reduce their risk of heart attacks, stroke and chest pain.
Researchers at 16 institutions had organized a long-running clinical trial to measure the effect of weight loss, enrolling more than 5,000 obese or overweight people ages 45 to 75 with Type 2 diabetes. They averaged about 200 pounds.
Half of the group was assigned to an intensive lifestyle intervention that involved eating less — 1,200 to 1,800 calories a day — and putting in at least three hours of moderate exercise a week. They got counseling and attended meetings to help them stick with the program.
Those people lost an average of 8.6 percent of their body weight in the first year, which isn't easy to do. Most weight-loss studies can eke out only a few percentage points of change in that time.
The people in the control group, who didn't get the lifestyle help, lost almost 1 percent of body weight in the first year.
Both groups managed to avoid major backsliding, which typically happens with weight-loss trials. The intervention group gained some weight back in years two through five, but ended up with a 6 percent loss over 10 years. The control group lost weight gradually, and was down about 4 percent at the end. All told, 1,193 people stayed with the trial throughout.
Excess weight is considered a risk factor for both cardiovascular disease and diabetes, so the researchers figured they'd see improvements in both.
Instead, they had to stop the trial early, after almost 10 years, when it was clear that the people in the weight-loss group weren't getting any extra protection from heart attacks, strokes, or angina.
But the trial wasn't a failure, the the researchers say. It shows that people with diabetes "can lose weight and maintain that weight loss," lead author Rena Wing, a professor of psychiatry at Brown University, reported at the American Diabetes Association meeting in Chicago. The results were published online in the New England Journal of Medicine.
The weight-loss group also had better glycemic control and lower systolic blood pressure, spent less money on medications, had less sleep apnea, and was more likely to have a partial remission of diabetes. They were less likely to land in the hospital. And they also felt better.
"This study in no way disproves the important of weight reduction and exercise," says Dr. Douglas Zipes, a distinguished professor emeritus at the Indiana University School of Medicine and past president of the American College of Cardiology. "There were significant benefits achieved."
The control group took more statins and other drugs to reduce cardiovascular risk, Zipes notes, which could have clouded the study's findings.
And he says that years of evidence showing that eating well and exercising reduce heart disease risk still stand. "We've been able to reduce mortality from heart disease by 60 percent over the past three decades," he said.