Effects of Increased Physical Activity/Exercise on Long-Term Losses in Weight and Waist Circumference: Serial Mediation from Changes in Exercise-Related to Eating-Related Self-Regulation.

Abstract

Behavioral obesity treatments have generally been unsuccessful at facilitating long-term weight reductions. Increased physical activity/exercise is a strong predictor of maintained weight loss. It has been proposed this is more linked to increases in exercise-related self-regulation carrying-over to eating-related self-regulation than through direct energy expenditures. Women with obesity participated in 10-month community-based behavioral treatments that had theory-based foci on either self-regulation skills building (n = 59) or knowledge of weight loss methods (n = 54). Physical activity/exercise, exercise-related self-regulation, and eating-related self-regulation were assessed at baseline and months 3, 6, and 12 in the prediction of weight and waist circumference changes over 24months. Significant overall improvements on all measures were found, which were significantly greater in the self-regulation-focused group than the knowledge-focused group. Mean reductions in waist circumference/weight were - 4.64cm/ - 5.17kg (- 5.5% of baseline weight) and - 0.66cm/ - 1.19kg (- 1.2% of baseline weight), respectively. Aggregated data indicated that early increase in physical activity/exercise significantly predicted 24-month reductions in both weight and waist circumference. Serial mediation analyses indicated that a sequential path from exercise-related self-regulation (baseline-month 3) → eating-related self-regulation (baseline-month 6) → eating-related self-regulation (baseline-month 12) fully mediated the physical activity/exercise-weight/waist circumference change relationships. Energy expenditures from physical activity/exercise accounted for 21% of lost weight. Findings of this field research supported benefits of progressively building self-regulation skills, first for physical activity/exercise then controlled eating, through accordingly focused behavioral treatments. Opportunities for tailoring large-scale community-based interventions grounded in theory were enhanced.