Effects of Self-regulatory Skill Usage on Weight Management Behaviours: Mediating Effects of Induced Self-efficacy Changes in Non-obese through Morbidly Obese Women
Objectives Self‐regulation is thought to play a role in overcoming barriers to weight management behaviour changes. This research assessed the extent that relationship is manifested through associated changes in self‐efficacy, and effects based on degree of obesity. Design Data sets from three previous studies of the present research group were utilized. After assessment of change scores using repeated‐measures ANOVA, mediation and moderation analyses assessed effects of changes in self‐regulatory skill usage on changes in physical activity and fruit/vegetable intake through self‐efficacy changes. Moderating effects of BMI were then assessed. Methods Women with body compositions ranging from non‐obese (BMI < 30 kg/m2) to those with morbid obesity (BMI ≥ 40 kg/m2) were administered similar cognitive‐behavioural treatments, and assessed on theory‐based psychosocial and behavioural measures over 6 months. Results From baseline to Month 6, changes in self‐regulation for physical activity and eating, physical activity behaviours, fruit/vegetable intake, and self‐efficacy for controlled eating were significant in non‐obese women (n = 48) and women with Class 1 (n = 43), Class 2 (n = 70), and Class 3 (n = 48) obesity. Positive effects were smaller in exercise self‐efficacy. For each of the BMI‐based groups, changes in self‐efficacy significantly mediated the prediction of physical activity and fruit/vegetable intake by changes in self‐regulation. In aggregated data, BMI significantly moderated the prediction of change in physical activity (higher BMI associated with a stronger association), but not fruit/vegetable intake, within those models. Conclusion Increasing self‐regulatory skills to overcome lifestyle barriers was found to be important for fostering improved weight loss behaviours, especially in the treatment of higher degrees of obesity in women.