Diet and exercise prevent diabetes

Clinical Question

Do diet and exercise delay the development of diabetes in high-risk patients?

Bottom Line

Diet and exercise are effective in delaying the diagnosis of diabetes in patients at increased risk. (LOE = 2b)


Lindstrom J, Ilanne-Parikka P, Peltonen M, et al, for the Finnish Diabetes Prevention Study Group. Sustained reduction in the incidence of type 2 diabetes by lifestyle intervention: follow-up of the Finnish Diabetes Prevention Study. Lancet 2006;368:1673-1679.  [PMID:17098085]

Study Design

Randomized controlled trial (nonblinded)


Industry + foundation




Outpatient (any)


In the Finnish Diabetes Prevention Study, 522 men and women, aged between 40 years and 65 years and at high risk for developing diabetes, were randomly assigned either to a tailored diet-and-exercise regimen or to usual care. To be eligible, the patients had to have a body mass index greater than 25 and have impaired glucose tolerance. The original study lasted a median of 4 years. The cumulative incidence of diabetes in the intervention group was 11% compared with 23% in the control group (number needed to treat = 8; 95% CI 6-16). In this report, the researchers provide 3 additional years of observations on the patients who had not developed diabetes by the end of the original study. No specific diet or exercise information was provided to the patients during this follow-up period. After a total of 7 years of follow-up, 75 patients in the intervention group and 110 patients in the control group developed diabetes. The cumulative incidence rate was 4.3 per 100 person-years in the intervention group, and 7.4 in the control group. The authors estimate that one would need to treat 22 patients with diet and exercise to prevent 1 patient per year from developing diabetes.