Objective: To investigate the effect of a nutrition education intervention and four hours of related teaching on the nutrition concepts of a sample of 9 year-old children. Design: Prepost test design. Children's food classification concepts were assessed before and after the intervention and nutrition teaching. Setting: Year 4 class of a suburban primary school in South Wales. Method: The children completed a food classification task before and after visiting a health promotion exhibition and receiving lessons emphasising food/health related concepts. Results: Comparison of the results before and after the intervention suggested that there was no significant change in the participant's conceptual understanding of food. Conclusion: Children's food classification concepts remain resistant to change despite enhanced exposure to nutrition information. (Contains 1 figure and 3 tables.)