Background. Few interventions have focused on a parent-based, home food-centered approach as a way to improve the relatively poor quality of US children's diets. This dissertation evaluated one such intervention by combining two theoretical models taken from the fields of health psychology/behavior change (Social Cognitive Theory; SCT) and health communication/persuasion (Heuristic-Systematic Model; HSM). The novel combination of these two theoretical orientations was intended to combine the often distinct fields of nutrition and communication to ultimately uncover new ways to improve child diet quality.Aims. 1) Explore whether and how the level of parent motivation and/or parent ability (education level) affects cognitive processing of the intervention materials by parents who receive intervention materials; 2) Compare intervention and control groups according to knowledge gain and change in key personal factors in the SCT (self-efficacy, outcome expectancies, skills); and 3) Compare intervention and control groups according to changes in parent attitudes toward healthy eating, parent diet quality, parent modeling behaviors, home food availability and accessibility, and child diet quality.Methods. A newly developed intervention package designed for low-income parents of 3-5 year old children in the Head Start preschool program was tested in an eight-week randomized controlled trial. Researchers recruited 42 participants who were randomized into control (n=19) and intervention (n=23) groups and who received the intervention package or nothing beyond Head Start materials, respectively. Researchers collected cognitive and dietary data and a home food inventory at pre-study (week 0) and post-study (week 8) in participant homes.Results. Analyses of HSM constructs in intervention participants (n=16 who remained in the study at week 8) revealed a significant positive relationship between the perceived similarity heuristic and change in parent attitude toward the child eating healthfully during the study (β=0.13, p=0.02) and significant negative relationship between systematic processing (number of correct responses on knowledge test) and parent attitude toward the child eating healthfully during the study (β=-0.09, p=0.02). The latter finding was in the opposite direction than expected. No other Aim 1analyses were significant. No significant changes in SCT, home food environment, or adult or child dietary constructs/measures were detectable in the intervention group compared to the control group, and thus, Aims 2 and 3 were not supported. Post-hoc analysis of the combined sample of intervention and control participants (n=35 who completed week 8) revealed significant correlations between many measured constructs, and a well-fitting path model (motivation and education → percent of nutrient-dense foods available in the home → adult diet quality → child diet quality) was identified that explained 15.4% of the variance in child diet quality.Conclusions and Implications. Post-hoc path analysis demonstrated the importance of the home food environment, particularly availability of nutrient-dense foods in the entire small sample of parents. Although there were few significant findings in processing intervention materials and no significant differences between the intervention and control groups in changes in attitude, theoretical, or behavior change, some trends in the data, particularly in the Social Cognitive Theory, home food environment, and adult diet quality variables presented interesting leads for future research.
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