Effective and scalable healthy eating interventions are needed that can help people of all ages, race/ethnicities, income levels, and health status consume more healthy foods. The challenge for researchers is to identify interventions capable of nudging entire populations to eat healthier foods to improve health and quality of life. "Agent of change" is a general term used to describe a person acting within an intervention to ultimately bring about change in another individual. The objectives of this dissertation were to create and evaluate two agents of change interventions designed to improve dietary intake.For the first intervention, twenty-one Michigan State University Extension Community Nutrition Instructors were trained to coach Michigan school child nutrition professionals (agents of change) to make changes to their school cafeterias designed to increase children's selection of fruits and vegetables. Sixty-seven school nutrition professionals completed a checklist of cafeteria practices before and after making cafeteria changes. Thirty schools submitted five days of pre- and post-food production records. Mean values of Scorecard totals and five-day average cups of fruits and vegetables selected per student as measured by schools' production records were calculated for pre- and post-cafeteria changes. Changes were assessed using t-tests. A regression analysis was conducted to determine if schools demonstrating greater improvement in their overall Scorecard also demonstrated increased selection of cups of fruits and vegetables per student. After coaching by the MSU Extension Community Nutrition Instructors, there were significant increases in the number of school cafeteria changes made, regardless of school grade, percentage of students participating in the school meal program, and whether the school formed a student team. There were no statistically significant improvements in the cups of fruits or vegetables selected by students after the cafeteria changes, and selection of fruits and vegetables was not associated with cafeteria improvements.For the second intervention, two cohorts of college students enrolled in similar asynchronous 14-week online introductory nutrition courses, one with and one without six agents of change assignments, were administered validated surveys to evaluate pre- and post-course dietary intake and nutrition knowledge. The agent of change assignments were designed for students to encourage their family and friends to increase intake of whole plant foods. Students were required to create six video presentations and encouraged but not required to share their videos with family members and/or friends. Regression analyses were conducted to determine associations between gender, perceived cost, taste, ease of eating, and dietary and nutrition knowledge before taking the course among students enrolled in the course with the agent of change assignments. College student mean intakes of whole grains, fiber, fruits and vegetables, and dairy did not meet U.S. recommended dietary guidelines daily intake levels and students consumed more added sugars and added sugars from sweetened beverages than recommendations. Perceived ease of eating healthy foods, perceived cost of healthy foods, and nutrition knowledge were all significantly associated with consumption of combined fruits and vegetables, vegetables, fruit, and dietary fiber. Students in both cohorts significantly increased their nutrition knowledge and decreased total added sugar intake over the course of the semester. Students in the cohort without the agent of change assignments also significantly increased their intakes of whole grain, fiber, and vegetables.Perceived changes in dietary-related knowledge, skills, and consumption of healthier foods were measured post course completion for the cohort with the agent of change assignments. Students in this cohort were divided into two groups: students who acted as agents of change (created and shared healthy eating videos with their friends and family members), and students who did not act as agents of change (created videos but did not share them). The agent of change group did not exhibit any significant differences in mean change in nutrition knowledge and dietary intake compared to students who did not act as agents of change. However, students who acted as agents of change demonstrated significantly greater perceived increases in nutrition knowledge and familiarity with, skills to eat and prepare, confidence, motivation, and consumption of healthy foods as compared to students who did not act as agents of change.Overall, this dissertation research adds to the healthy eating intervention literature by evaluating interventions using novel agent of change approaches in public school and university settings. It also demonstrates: 1) how public health organizations, public schools and nutrition interventionists might leverage partnerships with schools and universities to explore ways to use agents of change to reach large populations; 2) demonstrates the need for continued investigation into intervention elements required to change eating behaviors; and 3) highlights the need for further research to better understand and describe drivers of selection and consumption of healthier foods.
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