The purpose of this study was to investigate the effect of a dietary modification intervention programme by applying the Stages of Change Model in 2 h postprandial capillary glucose reduction among Thai population. A randomized control trial was conducted for people at risk of type 2 diabetes for a period of 8 weeks. The intervention programme consisted of evaluating an individual's stage of change after being provided dietary information regarding kind of food and portions, discussion with a role model, and keeping a food diary record. By the end of the intervention programme, most participants in the experimental group were in the action stage (n = 36), whereas those in the control group were in the preparation stage (n = 32). Body mass index, blood pressure, food consumption behaviour and the 2 h postprandial blood glucose (PPG) in the experimental group had improved (P < 0.05). When performing regression analysis, intervention participation and the 2 h PPG at the baseline accounted for approximately 54% of total variance in predicting the 2 h PPG. This study yielded evidence for the benefits of using the Stages of Change Model as a framework in a dietary modification programme among people at risk of type 2 diabetes.