Coaction of Exercise and Eating Improvements Within a Behavioral Obesity Treatment: Directionality and Psychological Mechanisms.

Purpose: Because coaction (a favorable change in one behavior increasing the probability of a similarly favorable change in another behavior) associated with health behaviors has been identified, directionalities of such relationships within weight-loss behaviors (e.g., exercise, healthy eating) and their theory-based psychological mechanisms requires more investigation. Method: Women with obesity and either disturbed mood (n = 61) or normal mood (n = 58) participated in a cogntive-behavioral weight-management treatment within a community setting. Analyses of both group differences, and mediation models using aggregate data of behavioral and psychological variables, were conducted. Results: Improvements in measures of self-regulation, self-efficacy, mood, exercise, and fruit/vegetable intake were significant overall; with fruit/vegetable increase greater in the disturbed mood group. The prediction of increase in fruits/vegetables from baseline-Month 6 by increase in exercise from bascline-Month 3 (β = .24) was stronger than effects of change in fruit/vegetabe intake on exercise (β = .16). Overall mediation models were significant where changes in self-regulation and self-efficacy were entered as serial mediators of predictions of fruit/vegetable change by change in exercise (R²= .35 and .32), and vice versa (R²= .24 and .23). Paths demonstrating effects through self-regulation change and self-efficacy change were significant in the prediction of eating and exercise changes, respectively. Conclusion: Contributions to advancements in behavioral theory and treatment curricula targeting self-regulation and self-efficacy to improve exercse-eating change relationships were suggested.  .