Evaluation of a planned behavior theory-based intervention programme to promote healthy eating

The objective of the study was to test the effectiveness of an intervention program based on the theoretical framework of the Theory of Planned Behavior, with the addition of attitude strength and role identity. The aim was to alter adolescents' healthy eating attitudes and behaviour. In the sample were 335 high school students, who were divided into intervention and control groups. The intervention lasted 12 weeks and included posters and lectures promoting healthy eating. The measures included a questionnaire assessing the hypothesis and a food frequency questionnaire which measured eating habits. Analysis showed the intervention was effective in proving attitudes toward healthy eating and attitude strength, intention, perceived behavioral control, and healthy eating behaviour, but not effective in predicting subjective norms and role identity. Results provide evidence that intervention changed attitudes toward a behavior in a school setting.