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Krukowski, Rebecca A.

Psychology

2007

PhD

Background: Previous research has indicated that exercise is an important predictor in the maintenance of weight loss; however, mediating variables in this relationship have not received as much attention. Methods: Within the context of a six-month behavioral weight control program and twelve-month maintenance program, 211 Caucasian women completed measures of physical activity, physiological functioning, calorie consumption, psychological functioning, and preference for fat at four time points (i.e., baseline, posttreatment, six-months post-treatment, and twelve-months post-treatment). This study used structural equation modeling to explore potential mediating factors in the relationship between exercise and post-treatment weight gain, including physiological factors (e.g., lean body mass, resting metabolic rate, and fitness level), psychological factors (e.g., body image, depression, anxiety, and stress), and quantity and composition (i.e., preference for fat) of the women's calorie consumption. Results: Physiological functioning was found to be a significant mediator in the relationship between both overall and moderate-to-vigorous physical activity and post-treatment weight gain (z=-2.04,p<.05). Moderate-to-vigorous activity significantly predicted lower calorie consumption(r=-0.17,p<.05), and calorie consumption was significantly predictive of post-treatment weight gain(r=0.20, p<.01); however, calorie consumption was not found to be a significant mediator in the relationship between exercise and post-treatment weight gain. Moderate-to-vigorous physical activity did predict lower psychological distress (r=-0.18, p<.05); however, psychological functioning, as a whole, was not predictive of post-treatment weight gain. A secondary analysis examining fat preference indicated that it was a significant mediator in the relationship between moderate-tovigorous activity and energy consumption (z=-2.27, p<.05). Conclusions: This research points to the importance of physiological factors in the maintenance of weight loss as well as the possibility that exercise may encourage women to control the quantity and quality of their caloric intake.