Impacts of early psychological changes on correlates of weight-loss maintenance: Seeking increased precision for sustained behavioural obesity treatment effects.

Issue addressed: Obesity is an increasing worldwide health issue. In affluent English-speaking countries, obesity ranges from ~28% (Australia) to ~42% (United States) of the adult population. Enabling weight loss beyond an initial 6 months is an unresolved challenge.

Methods: Women with obesity participated in community-based obesity treatments incorporating either cognitive-behavioural methods emphasizing self-regulatory skills development (n = 106) or typical information/education processes (n = 47). Psychosocial, behavioural, and weight changes were measured.

Results: Significant overall improvements in exercise-related self-regulation and self-efficacy, mood, physical activity/exercise (PA/exercise), diet, and weight were found from baseline-month 6 (weight-loss phase) and baseline-month 12, but not from months 6-12 (weight-loss maintenance phase). Significantly greater improvements were found in the cognitive-behavioural group. Within the weight-loss phase, changes in both PA/exercise and diet significantly contributed to the explained variance in weight loss, whereas within the weight-loss maintenance phase, only change in PA/exercise was a significant predictor. There was no significant relationship of weight loss across phases. Months 6-12 change in PA/exercise significantly mediated relationships of changes in self-regulation→weight, mood→weight, and self-efficacy→weight. Earlier scores and score changes in mood and self-efficacy significantly impacted the subsequent parallel relationships.

Conclusions: Cognitive-behavioural methods affect psychosocial changes leading to initial changes in diet, PA/exercise, and weight. Those changes then impact subsequent changes in PA/exercise-a primary malleable correlate of maintained weight loss. SO WHAT?: This research extended previous findings to better-inform behavioural obesity-treatment foci to address the pervasive public health problem of attaining and sustaining weight loss. Findings related to PA/exercise will help impact health-promotion outcomes.