Background: We sought to evaluate the effect of educational intervention based on the theory of planned behavior (TPB) on nutritional behaviors in relation to the cardiovascular disease (CVD) among health volunteers. Methods: In this quasi-experimental study, the participants included 128 active health volunteers. To conduct the study, 65 and 63 participants were randomly assigned into the intervention and control groups, respectively. Data were collected before and six weeks after the intervention using a validated researcher-made questionnaire. The questionnaire consisted of demographic variables, knowledge questions, and TPB constructs. Data were analyzed by Chi-square, t-test, Mann-Whitney U, and Wilcoxon test. Results: No significant difference was observed between the intervention and control groups with regard to the demographic characteristics, knowledge mean scores, and TPB constructs at the beginning of the study. However, the mean scores of knowledge, attitude, subjective norms, perceived behavioral control (PBC), and nutritional behavior increased significantly (P < 0.001, P < 0.001, P = 0.018, P = 0.007, and P < 0.001, respectively) in the intervention group six weeks after the beginning of study. Significant differences were observed in nutritional performance of the intervention group, in other words the nutritional behavior of the intervention group members changed during the intervention. Conclusion: The PBC was the strongest construct in attitude. To optimize nutritional interventions in preventing the CVD, TPB should be implemented in educational interventions.