Degree Type


Date of Award


Degree Name

Master of Science




Nutritional Sciences

First Advisor

Gregory J. Welk


Lifestyle changes are generally accepted as the most effective way to lose weight and keep it off. However, the mediating and moderating variables that play a role in behavior change need to be explored to determine how people change and what factors influence successful outcomes. Motivational interviewing and social support have been shown to aid in weight loss and healthy behaviors. Most behavior interventions consider success as weight loss or increased consumption of fruits and vegetables. However, those interventions are not specifically measuring the behavior associated with that target outcome. This study examines both the behavior and the outcome. The aims of this study were: (1) to determine if in-person or online health coaching was more effective in behavior change and (2) to evaluate the effects of social support on behavior change and respective outcomes. Eighty-seven participants self-selected into either in-person or online health coaching and also chose one of three goals to pursue: diet, physical activity, or weight management. The eight week behavioral intervention utilized motivational interviewing as the coaching theory. Behavior change strategies and social support were measured via a battery of surveys and weight, moderate/vigorous minutes, and diet records (evaluated using the Healthy Eating Index) were measured to quantify outcomes. A series of 2x3 (group by goal) ANOVAs were used to test effects on the behavior strategies as well as the outcome measures. Regression analyses were then conducted to examine the moderating impact of social support on the changes in strategies and outcomes. The results showed that participants in the in-person health coaching group had larger behavior change and objective outcomes than the online group with significant changes evident for the HEI outcome. With regards to the second aim, social support was found to be a significant predictor of improvements in behavior change strategies; however, it was not a significant predictor of the outcome measures. The results provide novel insights about behavior changes resulting from guided behavioral interventions as well as the relative effectiveness of in-person and online health coaching.


Copyright Owner

Kathryn Ann Bus



File Format


File Size

95 pages

Included in

Kinesiology Commons