At least 10 million overweight Americans could sharply cut their risk of developing diabetes by making relatively simple lifestyle changes in their diets and exercise routines.
The Diabetes Prevention Program is the first large study to show that losing weight and exercising can effectively delay diabetes in a wide range of overweight men and women who are just a step away from having full-blown diabetes.
While previous research has shown that diet and exercise can help control blood sugar levels in people who already have the disease -- and thus reduce some complications -- this study demonstrates that lifestyle changes can actually prevent diabetes in nearly 60 percent of those who are poised to develop the disease.
An estimated 16 million people in the United States have diabetes, a chronic disease of the pancreas that causes blood sugar levels to soar. Once largely limited to older adults, type 2 diabetes rates have tripled in the past 30 years, mostly because of the upsurge of obesity.
Diabetes strikes 800,000 people annually and is being diagnosed more frequently in younger individuals.
Minorities are at particular risk: Compared with whites, blacks have a 60 percent higher rate of developing diabetes and Hispanics have a 90 percent increased risk.
The disease costs an estimated $100 billion annually to treat in the United States; and with no proven way to prevent it, public health officials have become increasingly concerned about the future costs of the disease in an aging and increasingly overweight population.
Type 2, or adult-onset, diabetes is the most common form of the disease, accounting for 95 percent of cases in the United States. It is the leading cause of kidney failure, limb amputations and new blindness in adults. It also contributes to heart disease and stroke -- two of the major killers in the United States.
Until now, doctors believed that changes in diet and exercise might help reduce the risk of developing diabetes, but they had little scientific evidence to back up that thinking. Critics often pointed to the dismal failure of most people to lose weight and keep it off.
As little as a 5 percent weight loss -- that's about 10 pounds for most people in the study -- can reduce the risk of diabetes by 58 percent. That is truly remarkable.
During the three-year study, the participants in the lifestyle group reduced their risk of developing diabetes by a striking 58 percent. Among those 60 and older, the reduction in risk was even greater: 71 percent.
Participants in the lifestyle group met weekly, one-on-one, with a counselor for nearly six months. They received intensive instruction on diet and exercise, which was followed by group meetings on grocery shopping. The participants limited their food intake to 1,200 to 1,800 calories a day. They also exercised at least 30 minutes a day, five days a week, mostly by walking briskly.
On average, those who received the lifestyle counseling lost 7 percent of their body weight -- about 15 pounds -- and kept most of it off for the duration of the three-year study. Only about 5 percent of these participants developed diabetes each year -- half the rate of the control group.