Doctor of Philosophy (PhD)


Nutrition and Food Sciences

Document Type



The objectives of these studies were to validate and confirm the structure of a previously developed questionnaire that measures the psychosocial constructs defined by the Self-Determination Theory (SDT) and then test this questionnaire in a nutrition education setting. The instrument, titled the Motivation to Prepare Healthy Foods Questionnaire (MPHFQ), included items that measured intrinsic motivation, perceived competence, relatedness, autonomy, and autonomy support. These studies evaluated the questionnaire’s validity and ability to measure changes in the SDT construct scores.

The MPHFQ is a previously developed and reliable instrument intended to measure adults’ intrinsic motivation and perceived competence to prepare healthy foods, their feelings of relatedness toward peers, autonomy, and perceived autonomy support received in a classroom setting. The first study aimed to confirm the five-factor structure provided by the exploratory factor analysis (EFA) of the MPHFQ through confirmatory factor analysis (CFA) and respecification analysis. A total of 507 college students were recruited for the EFA in the first study; 492 responses were analyzed after removing missing data. The EFA provided sufficient support for the hypothesized five-factor model which provided the basis for the CFA and respecification analysis. For these analyses, 520 college students were recruited to complete the MPHFQ; 309 of these responses were randomized to the CFA and the remaining 211 responses were used to complete the respecification analysis. The fit indices provided by the CFA and respecification analysis confirmed the five-factor model. The fit indices for the CFA and respecification analysis, respectively, were as follows: Root Mean Squared Error of Approximation (RMSEA) = 0.56 and 0.055; Comparative Fit Index (CFI) = 0.94 and 0.94; Non-normed Index (NNI) = 0.93 and 0.93; and Standard Root Mean Square Residual (SRMR) = 0.050 and 0.057.

In the second study, the MPHFQ’s ability to measure changes in adults’ intrinsic motivation and perceived competence as a result of participating in a SNAP-Ed nutrition education and culinary skills-building program was examined. The instrument was administered to SNAP-Ed participants prior to the start of the program and again at the conclusion. A total of 47 SNAP-Ed participants responded to the survey. Perceived competence to prepare healthy foods significantly increased at the completion of the program (pp



Committee Chair

Tuuri, Georgianna