Reductions in negative mood in minimally versus moderately active women at behavioral obesity intervention start: Assessing floor effects and internal mechanisms of change to inform future treatments.

BACKGROUND

Due to minimal effects, new directions for behavioral (non-pharmacologic/non-surgical) obesity interventions are required. Previous research suggests that physical activity and exercise (PA/exercise) might have considerable merit for weight reduction via impacts on mood and other psychosocial correlates of controlled eating. Although as few as 3 bouts/week of low-moderate intensity PA/exercise are associated with improved mood-with no dose-response effect beyond that frequency-it is unknown if mood improvements may be leveraged when participants already complete ⩾3 bouts/week by treatment start.

OBJECTIVES

The present research addressed gaps in the available PA/exercise-psychosocial change-weight management research.

DESIGN

This study combined group contrasts with mediation analyses.

METHODS

Women participating in a community-based cognitive-behavioral obesity treatment emphasizing the increase of PA/exercise and exercise-related self-regulation and self-efficacy (N = 99) were divided for separate analyses into groupings of <3 bouts/week, and ⩾3 bouts/week, of light (e.g., easy walking) and moderate (e.g., fast walking) PA/exercise regularly completed prior to treatment start. The participants were assessed on psychosocial and PA/exercise changes from baseline to month 3.

RESULTS

Reductions in total mood disturbance (TMD), depression, and anxiety scores were overall significant, with no significant difference by exercise-frequency grouping. PA/exercise increases were significantly greater in the <3 bouts/week groupings. Change in self-regulatory skills usage mediated relations between groupings and changes in TMD, depression, and anxiety. In subsequent serial mediation models, significant paths from grouping → self-regulation change → self-efficacy change → TMD and depression changes were found.

CONCLUSION

Whether or not ⩾3 bouts/week of PA/exercise are completed at intervention start, TMD, depression, and anxiety may be reduced through treatment foci on increasing PA/exercise, self-regulation, and self-efficacy. Findings might be useful for informing scalable obesity treatments.