Group versus one-to-one multi-component lifestyle interventions for weight management: a systematic review and meta-analysis of randomised controlled trials

Background: Multi-component lifestyle interventions that incorporate diet, physical activity and behaviour change are effective for weight management. However, it is not clear whether delivery in a group or one-to-one format influences weight loss efficacy. The present study aimed to systematically review the evidence of the effectiveness of group compared to one-to-one multi-component lifestyle interventions for weight management.

Methods: MEDLINE, EMBASE, CINAHL, CENTRAL and ISRCTN databases were searched from inception up to February 2020 for randomised controlled trials comparing group versus one-to-one multi-component lifestyle interventions for weight loss in adults with a body mass index ≥ 25 kg m^-2 . The primary outcome was weight loss (kg) at 12 months and the secondary outcome was attainment of ≥5% weight loss at 12 months. Risk of bias was assessed using the Cochrane Risk of Bias Tool. Meta-analysis used random effects and estimated risk ratios and continuous inverse variance methods. Heterogeneity was investigated using I² statistics and sensitivity analyses.

Results: Seven randomised controlled trials with 2576 participants were included. Group interventions were favoured over one-to-one interventions for weight loss at 12 months (-1.9 kg, 95% confidence interval = -1.3 to -2.6; I² = 99%). Participants of group interventions were more likely to attain ≥5% weight loss at 12 months relative to one-to-one interventions (relative risk = 1.58, 95% confidence interval = 1.25-2.00; I² = 60%).

Conclusions: Group multi-component lifestyle interventions are superior for weight loss compared to one-to-one interventions with respect to adult weight management. Further research is required to determine whether specific components of group interventions can explain the superiority of weight loss outcomes in group interventions.