A Step or Two Against Diabetes

By Christine Gorman

The evidence continues to mount that you don't have to run marathons or lose all the weight you've gained since college to have a positive effect on your health. Consider diabetes. In recent years the U.S. has seen an alarming upswing in the incidence of Type 2 (or adult-onset) diabetes. But now it turns out that those prone to this life-endangering disease can cut their risk by more than half if they make modest changes in diet and exercise, according to a study released last week by the National Institute of Diabetes and Digestive and Kidney Diseases. Indeed, the research showed that lifestyle changes are much more effective in preventing the condition than treatment with an antidiabetes drug called metformin.

What makes the results so compelling is how broadly applicable they are. "These were not unusual people," says Dr. David Nathan, a diabetes expert at Massachusetts General Hospital in Boston who chaired the study. "There are 10 million Americans who look just like our folks."

The 3,234 study participants were overweight; ranged in age from 25 to 85; and included African Americans, Hispanic Americans and other ethnic groups that are, for reasons that remain unclear, particularly susceptible to developing diabetes. In addition, all the test subjects had trouble metabolizing glucose. Yet the lifestyle changes were clearly beneficial in each of these categories, with those over 60 showing the most improvement.

The greatest benefits occurred among test subjects who were physically active at least 30 minutes a day five days a week and who lost between 5% and 7% of their body weight, or an average of 15 lbs. Most chose walking as their preferred form of exercise. They also cut back on their total caloric intake and the amount of fat they ate. The goal was to consume 25% of calories from fat (compared with 30% to 35% in the average American's diet). For someone who eats 1,500 calories a day, that translates to 42 grams of fat. (Chomp down on a Big Mac and medium fries and you're already 14 grams over the limit.)

Just because the changes were modest, however, doesn't mean they were easy to implement. All the study volunteers were told to exercise and lose some weight. But it was those who had help figuring out what needed to change in their eating habits and how to work a daily walk into their routine who maintained their weight loss. It's not yet clear whether these lifestyle changes can actually prevent Type 2 diabetes or merely delay its onset for a few years. But a third of this group saw their blood-sugar levels fall back to normal--an especially encouraging sign. Losing a few pounds and walking 30 minutes a day are goals well within everyone's reach.

Visit www.niddk.nih.gov for more info. E-mail Christine at gorman@time.com