Social comparisons between group members during behavioural weight loss treatment: comparison direction, scale, and associations with weight loss maintenance

Objective: To examine distinct types of social comparisons (i.e. self-evaluations relative to others) in behavioural weight loss groups and their relations with weight loss maintenance. Design: Participants (N = 127, M_BMI = 35.66 kg/m²) reported on their comparisons at mid-treatment (6 months), including identification of their primary individual comparison target (group member) and perceptions of their own treatment adherence versus that of their group and identified target. Main Outcome Measures: Weight was assessed at baseline, mid-treatment, end-of-treatment (12 months), and 18- and 24-month follow-ups. Results: Comparisons with individual targets perceived as more successful with weight loss were most frequent (i.e. upward comparisons), though comparisons differed based on group versus individual targets and specific treatment behaviours (e.g. self-monitoring). Comparisons did not align with participants’ own treatment progress, suggesting that comparisons reflect more than just their objective weight loss relative to others. Relations between participants’ initial weight loss and maintenance was moderated by the type of individual target identified at mid-treatment (p = 0.02, sr = 0.27). Conclusions: Social comparisons in group-based weight loss treatment are multifaceted and predict long-term weight loss maintenance. Additional work is needed to determine how best to harness comparison processes to promote success in behavioural weight loss treatment.