Mediation of the relationship of behavioural treatment type and changes in psychological predictors of healthy eating by body satisfaction changes in women with obesity
Problem Psychological correlates of both short- and long-term weight loss are poorly understood. Changes in satisfaction with one's body might serve to motivate healthier eating by mediating treatments’ effect on psychological factors previously suggested to be associated with weight loss. Methods Women with obesity (age 48.6 ± 7.1 years; BMI 35.4 ± 3.3 kg/m2) were randomly assigned to social cognitive theory-based weight-management treatments that were either group sessions emphasizing physical activity-derived self-regulation (experimental; n = 53) or review of a written manual and phone support (comparison; n = 54). Changes in weight, physical activity, body satisfaction, negative mood, and self-efficacy and self-regulation for controlled eating were assessed over 3, 6, 12, and 24 months. Results The experimental treatment was associated with significantly more favourable changes across variables. Over 6, 12, and 24 months, body satisfaction change mediated relationships between treatment type and changes in each of the psychological predictors of healthier eating (mood, self-efficacy, self-regulation). Reciprocal, mutually reinforcing, relationships between changes in body satisfaction and those psychological predictors were also found. Increased physical activity was associated with improved body satisfaction, even after controlling for weight changes. Conclusion Findings increased understandings of the role of body satisfaction in improving psychological predictors of healthier eating over both the short- and longer-term. Results also suggested that body satisfaction could be improved through increased physical activity, irrespective of change in weight. Although results were limited to women with class 1 and 2 obesity, findings on interactions of psychological factors associated with eating changes have implications for the architecture of improved behavioural treatments.