This study aims to test the utility of the theory of planned behavior (TPB) for explaining intention to eat a healthful diet in a sample of Southeastern US office workers.
Participants in a worksite nutrition study (n = 357) were invited to complete an online questionnaire including measures of TPB constructs at baseline. The questionnaire included valid and reliable measures of TPB constructs: behavioral beliefs, normative beliefs, control beliefs, attitudes toward behavior, subjective norm, perceived behavioral control and intention. Data were collected from 217 participants (60.8 per cent response rate). Confirmatory factor analysis and structural equation modeling were conducted to test the hypothesized TPB model.
The model fit was satisfactory (χ2 = p < 0.0001, RMSEA = 0.06, CFI = 0.91, TLI = 0.90, SRMR = 0.09). All structural relationships between TPB constructs were statistically significant in the hypothesized direction (p < 0.05). Attitude toward behavior, subjective norm and perceived behavioral control were positively associated with intention (R2 = 0.56). Of all TPB constructs, the influence of perceived behavioral control on intention was the strongest (β = 0.62, p < 0.001).
Based on this sample of Southeastern US office workers, TPB-based interventions may improve intention to eat a healthful diet. Interventions that strengthen perceived control over internal and external factors that inhibit healthful eating may be particularly effective in positively affecting intention to eat a healthful diet, and subsequent food intake.
