OBJECTIVES: The aim of this review was to assess whether lifestyle education programs significantly improve glucose levels or lower the incidence of type-2 diabetes in people at high risk, compared with conventional education programs. METHODS: English language trials assessing lifestyle interventions (physical exercise, diet control and counselling programs) compared to usual care controls were searched via electronic databases. Two investigators independently reviewed abstracts and included studies in which subjects had impaired glucose tolerance, impaired fasting glucose or borderline values. Data was extracted from each included full-text publication. The outcomes of interest included change in glucose levels two hours after a 75g oral glucose load, change in fasting plasma glucose levels, and cumulative diabetes incidence during the intervention period. RESULTS: Eleven citations met the eligibility criteria, out of 198 retrieved from the databases. Of these, only four presented sufficient data for meta-analysis. Meta-analysis of two studies indicated that the decrease from baseline in 2-hour plasma glucose was significantly greater in the lifestyle intervention group than in the control group (WMD = -11.292 mg/dL, 95% CI: -17.718, -4.866). Results were similar for fasting plasma glucose, with a fixed-effects meta-analyses of data from the same two studies showing a significantly greater decrease from baseline in the intervention group compared to control (fixed effects WMD = -2.158 mg/dL, 95% CI: -4.239, -0.077). Meta-analysis of two other studies indicated that the cumulative diabetes incidence in the lifestyle intervention group was significantly lower than in the control group (fixed effects RR = 0.619, 95% CI: 0.522, 0.733). CONCLUSIONS: Structured lifestyle interventions involving a healthy diet and physical activity are an effective way to treat, prevent, and possibly delay type-2 diabetes. If lifestyle interventions are cost-effective from a health system perspective, they should be more frequently considered as a valid treatment option.