Development and validation of a healthy diet and physical activity tool based on health action process approach among patients undergone bariatric surgery.

Background: The purpose of this study was to develop and evaluate the validity and reliability of a healthy diet and physical activity assessment tool among patients one year after bariatric surgery based on Health Action Process Approach. Methods: We compiled 53 items based on healthy diet and physical activity behaviors among patients undergone bariatric surgery through reviewing the literature. Using quantitative and qualitative methods, and a panel of experts, we evaluated the face and content validities of the tool. The reliability was evaluated by Intra-class correlation coefficient and Cronbach's alpha. Results: The content validity ratio and the content validity index were 0.62 and 0.79, respectively. Exploratory factor analysis showed seven factors, including risk perception, outcome expectations, task self-efficacy, coping, recovery self-efficacy, action planning, coping planning, and behavioral intentions. The Intra-class correlation coefficient was between 0.8 and 0.91; and Cronbach's alpha for different constructs was between 0.8 and 0.95. Conclusion: The findings showed that the constructs of the Health Action Process Approach tool regarding healthy diet and physical activity had adequate validity and reliability in bariatric surgery patients.