Take 5,000 overweight diabetics between the ages of 45 and 75 and divide them into two groups. One group will exercise and eat less in an effort to lose at least 7 percent of their body weight. The other will take whatever medications their doctor prescribes and learn about their disease, but that's all.
What's going to happen?
Obviously, members of the diet-and-exercise group will have fewer heart attacks and strokes, and most of them will live longer, right?
Actually, that's not what happened in a study named "Look AHEAD (Action for Health in Diabetes)". As reported in the New England Journal of Medicine, the diet-and-exercise group lost 6 percent of their body weight on average, while members of the other group lost 3.5 percent. A weight loss of just 5 percent has been shown to improve control of blood pressure, blood sugar and cholesterol, and members of the diet-exercise group experienced all those benefits.
Yet, after nearly 10 years, the study was suspended due to "futility" -- the two groups barely differed in the number of "cardiovascular events" (heart attacks and strokes) they experienced.
How can this be? Could the traditional advice about controlling diabetes be wrong?
Maybe, but other explanations might account for the results, according to the authors of the study.
For example, members of the group who received only medical treatment might have received very good treatment, including medications to control their cholesterol, blood pressure and blood sugar. Members of the diet-exercise group, in contrast, needed less medical management and obtained benefits that may not have become apparent during the 10 years of the study. In other words, members of the group that received only medical management may suffer more cardiovascular events someday, but not yet.
Also, members of the diet-exercise group clearly experienced benefits, such as less sleep apnea, more energy, better emotional health and, in some cases, a remission of diabetes.
"We kept hearing them say, 'I can keep up with my grandchildren now,'" said Dr. John Jakicic of the University of Pittsburgh, the principal investigator of the study. "They remained more functional and became less disabled during the study."
Besides, controlling diabetes through diet and exercise means less reliance on expensive medications, Jakicic added.
And although the people in the medical-management group received excellent treatment even though they didn't engage in an intensive program of diet and exercise, that may not be the case for everyone who has diabetes.
''You hope your physician is managing your risk factors well, but that's not always going to happen," Jakicic said.
The best strategy, in his opinion, is to pursue the benefits of both groups in the study. Seek the best medical management of your diabetes you can find, and try to lose weight through diet and exercise.
"Do both," he said. "If you're a diabetic, you can benefit from a healthy lifestyle, even if that just means a better quality of life."