Date of Award

Summer 2021

Document Type

Open Access Dissertation


Exercise Science

First Advisor

Michael W. Beets


National dietary guidelines recommend that children’s diets consist of fruits, vegetables and whole grains, while limiting high-fat foods. Studies indicate, however, that children consume an abundance of sugar-sweetened, calorically dense foods and are lacking in fruit and vegetables, behaviors which significantly contribute to high rates of childhood obesity and subsequent, lifelong, detrimental health impacts. This dissertation provides new knowledge to strengthen the evidence-base and inform future best practices in youth nutrition programming so that more children will have the opportunity to meet national dietary recommendations. Three distinct investigations sought to 1) examine current and past youth dietary intake by comparing the most common foods consumed by children and adolescents (ages 2-18 years) at each daily eating occasion (breakfast, lunch, dinner, snacks), evaluated as a whole and by age groups, in 1971-1974 and 2009-2010 2) evaluate the effectiveness of the Food & Fun After School (FFAS) curriculum on changes in dietary knowledge, dietary self-efficacy and snack preferences of children in afterschool programs (ASPs) 3) utilize an iterative literature review examining best-practices of train-the-trainer (TtT) program delivery to develop a conceptual model for TtT use in research and practice.

Study 1 showed youth dietary intake, in terms of food groups and items consumed, was largely similar in 2009 and 1977. Youth in 2009, however, have swapped fat, in the form of beef, for carbohydrates, in the form of refined carbohydrates and added sugars, in their overall daily diet. These critical differences coincide with changes to the national food industry over the same period, largely driven by convenience, advertising, and policy.

In the second study, significant improvements in food knowledge were found for intervention students compared to controls. No significant effects were seen for self-efficacy to consume FV. During snack 1, when only served a choice of FV, over 93% of all children selected a FV at pre and post-test. This is compared to less than 10% of children selecting a FV at pre and post-test during snack 2, when less-healthful alternatives were also served. The intervention had a significant effect on fully consumed FV and FV waste for snack 2 among the small percentage of children who selected FV. These small significant improvements in food knowledge, FV consumption, and waste reduction for youth in intervention afterschool programs (ASPs) suggest curricula combined with structural controls on the foods offered for snack could enhance youth dietary knowledge and habits in the ASP setting.

The third study describes a conceptual model that identifies the critical factors necessary for interventions to effectively use and evaluate TtT. These critical considerations include the number of tiers, or training cohorts, with multiple tiers required for a full TtT approach, purposive selection of trainers, training on pedagogical techniques and program content, expansion of the reach of experts, the dampening of the effect with the addition of tiers, and the evaluation of implementation and costs throughout all tiers from stakeholders to expert instructors, facilitators, and eventually to the target population. With the consensus on TtT use provided by this model, program delivery has the potential to be not only more efficient but ultimately more impactful, creating true population level change on a broad public health scale.


© 2021, Rebecca Kyryliuk