**2. The preventive effect of CR on T2DM**

As a lifestyle intervention method, it is very important to make sure whether this thera‐ py can prevent T2DM from occurrence in the high risk persons. Tuomilehto et al. [5] had assigned 552 middle-aged, overweight subjects with impaired glucose tolerance to either the intervention group or the control group. Each subject in the intervention group received individualized counseling aimed at reducing weight, total intake of fat, and intake of saturated fat and increasing intake of fiber and physical activity. After 3.2 years followup, they found that the cumulative incidence of diabetes was 11 percent (95% confidence interval, 6% to 15%) in the intervention group and 23% (95% confidence interval, 17% to 29%) in the control group, moreover, during the trial, the risk of diabetes was reduced by 58% (P<0.001) in the intervention group. The next year, another larger sample follow-up study focused on the lifestyle intervention on diabetes prevention, including CR, exercise, et al. Three years follow-up later, CR reduced the incidence by 58% (95% confidence interval, 48% to 66%), as compared with placebo [6]. These studies provided satisfactory evidences on the preventive effect of CR on T2DM.
