While Americans' increasing waistlines and the associated health problems have been making headlines, US researchers have been examining whether adopting a healthful diet and regular physical activity can prevent type 2 diabetes. Type 2 is the most common form of diabetes and is often associated with being overweight and sedentary.

Multi-center study

The Diabetes Prevention Program Research Group involved over 3200 adults. The participants were at least slightly overweight, and blood sugar measurements indicated they were at risk for developing type 2 diabetes, according to the American Diabetes Association standards.

The volunteers were randomly assigned to one of three treatment groups; standard lifestyle recommendations (diet and exercise) plus metformin (Glucophage®), a medication that controls blood sugar; the same standard lifestyle information plus a placebo pill; or, an intensive lifestyle modification program with no medication or placebo.

The standard lifestyle information consisted of written guidelines for healthful eating, weight reduction, and information about the importance of physical activity. In contrast, the intensive lifestyle modification program was a more rigorous, 16-lesson curriculum designed to help participants achieve a 7% weight loss through a healthful low-fat, low-calorie diet and at least 150 minutes each week of moderate physical activity. This program was designed to be flexible and culturally sensitive, and was taught individually during the first 24 weeks with subsequent group sessions for support. For the next several years, the volunteers were monitored for the development of type 2 diabetes.

Promising results

Participants assigned to the intensive lifestyle intervention group successfully made some healthful changes. On average, they decreased their daily food intake by 450 calories and lowered fat intake by almost 7%. Over half met the physical activity goal. The group lost an average of 12 lbs, significantly more than the other two groups.

Not surprisingly, health benefits accompanied these changes. The incidence of diabetes was 58% lower in the group that received the intensive lifestyle intervention compared with the placebo group. Those in the standard lifestyle plus metformin group also had a reduction in diabetes incidence - 31% compared with the placebo. Clearly, weight loss and exercise were more effective than medication in reducing the risk of diabetes.

Weight loss as preventive medicine

Even though all volunteers were provided with diet and exercise information, the success of the intensive program indicates that results depend on more than good intentions and knowledge. While those in the standard groups were given diet and exercise guidelines, the intensive program also provided support, behavior modification strategies, and individualized counseling -- all of which are crucial when making long-term commitments to lifestyle changes.

An estimated 10 million people in the United States are similar to the volunteers in this study in terms of age, weight, and blood sugar measurements and therefore at risk for developing type 2 diabetes and the accompanying complications of heart disease, kidney problems, and nerve damage. If the profile sounds familiar, implementing these same healthful strategies - a low-fat, low-calorie diet and at least 20 minutes each day of moderate activity, like brisk walking - may be the best way to reduce your risk of type 2 diabetes.