Investigating fruit and vegetable consumption using the transtheoretical model

Purpose: Test the applicability of the transtheoretical model (TTM) to adult fruit/vegetable consumption. Design: Cross-sectional random-digit dial survey. Setting: Hawaii. Subjects: 700 (62.6% female; age [mean ± SD], 47 ± 17.1 years; education [mean ± SD], 14.6 ± 2.8 years; 35.0% white, 31.1% Asian, 22.1% native Hawaiian/Pacific Islander, 11.8% other). Measures: Stages, processes, self-efficacy, decisional balance, and self-reported fruit/vegetable consumption. Analysis: Confirmatory factor analysis tested the factor structure. Analyses of variance xvere used to explore stage differences in constructs. Results: Stage distribution luas precontemplation (33 %), contemplation (4 %), preparation (37%), action (3%), and maintenance (23%). A 10-factor process model with two higher-order correlated factors (experiential and behavioral) provided the best data fit (χ² = 1446.12; df= 366; p <.0001; comparative fit index [CFI] =.89; standardized root mean square residual [SRMR] =.05). The self-efficacy structure fit the data well (χ²= 81.86; df= 9;p<.0001; CFI=.94;SRMR =.04), as did the decisional balance structure (χ²= 37.42; df= 19; p=.007; CFI =.99;SRMR =.02). Processes, self-efficacy, decisional balance, and fruit/vegetable consumption behavior differed significantly by stage, with medium effect sizes for most variables. Conclusion: The variables revealed adequate fit to the theorized measurement models. TIM predictions regarding stage differences in self-efficacy, pros and cons, and fruit/vegetable consumption were confirmed; however, most experiential and behavioral processes increased in the early stages and then leveled off.