A study by the national institute of diabetes and digestive and kidney diseases conducted from 1998 to 2001 in people at high risk for type 2 diabetes. All study participants had impaired glucose tolerance, also called pre-diabetes, and were overweight. The study showed that people who lost 5 to 7 percent of their body weight through a low-fat, low-calorie diet and moderate physical activity—usually walking for 30 minutes 5 days a week—reduced their risk of getting type 2 diabetes by 58 percent. Participants who received treatment with the oral diabetes drug metformin reduced their risk of getting type 2 diabetes by 31 percent.