The Diabetes Prevention Program (DPP) was the first nationwide U.S. study to examine whether type 2 diabetes could be prevented or delayed through diet and exercise or medication. Sponsored by the National Institutes of Health, the study involved more than 3,200 adults diagnosed with prediabetes.

Begun in 1995, the three-year study confirmed that people at high risk for type 2 diabetes could prevent or delay the onset of the condition by making important changes to diet and exercise. Metformin, an antidiabetic agent, also helped lower risk, but its effects were less dramatic than changes to lifestyle.

Thirty minutes a day of moderate exercise five times a week, combined with a 5 to 7 percent reduction in body weight, resulted in a 58 percent reduction in diabetes among participants. Diet and exercise demonstrated even greater benefits in patients 60 years and older.

The results prompted the study's monitoring board to end the trial a year early because the data had answered the research questions.

Scientists continue to mine new data from the DPP, such as recent findings that the eye disease diabetic retinopathy can affect people with prediabetes. With rates of obesity, prediabetes and type 2 diabetes soaring, the Diabetes Prevention Program remains relevant.