Objective: The aim of this study was to examine the effects of nutrition education programme using the Convenient, Attractive, Normative (CAN) framework to facilitate changes in mindset, attitudes and behaviours towards food among high-school male baseball players. Design: Quasi-experimental design. Setting: Two public high schools in Osaka, Japan. Methods: Students in two high schools (mean age±SD, 16.6±.5years) participated in the study. One school served as an intervention group (n=28) and received the CAN nutrition education programme. The other school served as a control group (n=22), and students within it did not receive the intervention. Students in the intervention group received three nutrition lecture sessions and face-to-face individual nutritional guidance over a 4month intervention period. Before and after the intervention, all students were asked to record their food and beverage intake by taking food pictures, recording portion weights and sending these to the project dietitian. They were also asked to develop a dietary behaviour plan for meeting their goals. At the end of the intervention, they were asked about their experiences. Results: Students in the intervention improved their food intake, dietary balance and athletic performance. Bat swing speed was significantly faster following the intervention. Body weight increased without changing lean body mass in both groups. Conclusion: Results suggest that a CAN nutrition education programme may be effective in increasing motivation and promote dietary behaviour change among male adolescent athletes. Future interventions should examine these motivational processes and investigate the factors contributing to well-balanced meals.