One Out of Three U.S. Adults Have Prediabetes

Nine Out of Ten of Them Don’t Know It


People have prediabetes if their blood sugar is higher than normal, but not high enough to be diagnosed with type 2 diabetes. Prediabetes puts you on the road to developing type 2 diabetes as well as heart disease and other health problems.

Not sure if you have prediabetes? Only a blood test can tell for sure, but to get an idea you can calculate your risk by going to doihaveprediabetes.org.

The good news: a healthy diet and exercise can cut diabetes risk in half. And that’s for people whose risk is already high.

So what’s the evidence, and how do you do it?

The Diabetes Prevention Program Study

“It’s amazing that a study on lifestyle, not medication, has changed the way we care for patients,” says Judith Wylie-Rosett, who heads the division of health promotion and nutrition research at the Albert Einstein College of Medicine in New York.

In 2001, researchers halted the study a year early because the difference between groups was so stark.

“The lifestyle group had a 58 percent lower risk of diabetes than the placebo group,” says Wylie-Rosett, who was one of the DPP investigators. Results were similar in trials in Europe and Asia.2

Metformin cut the risk of diabetes by only 31 percent.

“And the risk dropped by 70 percent among people in the lifestyle group who were over 60,” notes Wylie-Rosett. “It was really dramatic.”

What mattered most: whether the participants lost weight, even though they didn’t lose much.

“The weight loss was 7 percent of their body weight at six months, and by three years it was only 5 percent,” says Wylie-​Rosett.

The exercise goal—150 minutes a week—mattered, but not as much.

“Weight is the dominant factor over time. But if you look at people who didn’t meet the weight-loss goal, physical activity had an effect. The takeaway is that even if you don’t lose much weight, you may reduce your risk of diabetes if you’re physically active.”

What’s more, since the study ended, many participants have regained much of the weight they lost. But if you count the number who now have diabetes, it’s still 27 percent lower in the lifestyle group than in the placebo group.3

“That suggests that there’s a legacy effect, so that if you lose weight, even if you regain it, there’s a positive long-term impact of that period of weight loss,” explained Rena Wing, a DPP investigator at Brown University, to members of the National Academy of Medicine in October.

“We investigators were probably as surprised as others that the program had a long-term effect even after people regained weight,” says Wylie-​Rosett. “The bottom line is that a healthy lifestyle may lower the risk of diabetes even if you can’t see it on the scale.”

How to Find a DPP Near You

Are you interested in trying the DPP? You can join programs offered online or by local groups across the country.

“It could be anything from a church to a health system to the YMCA,” says Wylie-Rosett. “As long as programs meet standards set by the Centers for Disease Control and Prevention, they’re covered by some insurance plans and, starting in 2018, by Medicare.”

Click here to find a program in your area.


N. Engl. J. Med. 346: 393, 2002.
2  Ann. Intern. Med. 163: 437, 2015.
Lancet Diabetes Endocrinol. 3: 866, 2015.

Photo: © Jacek Chabraszewski/fotolia.com.

Find this article interesting and useful? Nutrition Action Healthletter subscribers regularly get sound, timely information about staying healthy with diet and exercise, delicious recipes, and detailed analyses of the healthy and unhealthy foods in supermarkets and restaurants. If you don’t already subscribe to the world’s most popular nutrition newsletter, click here to join hundreds of thousands of fellow health-minded consumers.