The study, published online in the Journal of General Internal Medicine, found people with prediabetes — blood sugar levels higher than normal but not yet high enough to be classified as Type 2 diabetes — who lose weight within six months of their diagnosis were able to prevent diabetes over the next three years.

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The findings, investigators say, offer compelling evidence that even minor short-term behavioral changes can lead to major long-term health gains.
 

"We have known for some time that the greater the weight loss, the lower your risk of diabetes," said lead researcher Nisa Maruthur, M.D., an assistant professor in the Division of General Internal Medicine at the Johns Hopkins University School of Medicine.
 

"Now we understand that we can see much of the benefit of losing that weight in those first six months when people are adjusting to a new way to eating and exercising.
Substantial weight loss in the short term clearly should go a long way toward preventing diabetes."
 

Preventing prediabetes from becoming full-blown diabetes is important, Maruthur said, noting uncontrolled diabetes — marked by excess sugar in the blood — can lead to eye, kidney, and nerve damage, as well as cardiovascular disease.
 

For the study, Maruthur and her colleagues tracked more than 3,000 overweight, hyperglycemic people between for an average of 3.2 years at 27 academic medical centers. Participants were randomly assigned to receive doses of the diabetes drug metformin, an inactive placebo, or pressed to lose weight through dietary changes and exercise.
 

Participants in the weight-loss group were advised about better eating habits, directed to exercise 150 minutes a week, and given one-on-one counseling for the first six months and group counseling thereafter. The results showed those individuals who dropped 10 percent or more of their body weight had an 85 percent reduction in their risk of developing diabetes within three years. Even those who lost 5 percent to 7 percent of their body weight reduced their risk of developing diabetes by 54 percent.
 

Those given metformin, a drug that prevents the liver from producing too much glucose, did not lose significant amounts of weight, but their blood sugar levels were significantly lowered in six months of taking the medication — resulting in a reduced risk of developing diabetes as well.
 

The lowest risk, Maruthur says, occurred in patients who lost weight and also lowered the amount of glucose in their blood, as measured by a blood test taken after fasting.
 

"I'm usually thrilled if a patient loses 3 to 5 percent of his or her body weight after six months, but based on this new knowledge, if patients aren't losing more weight and if their glucose remains elevated, it might be time to escalate treatment by prescribing metformin," she says.
 

Maruthur says few doctors use metformin in patients with prediabetes, but the new study suggests it might make sense for those who are unable or unwilling to lose substantial weight in the short term.

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The study was funded, in part, by the National Institutes of Health.