Abstract
Guidelines recommend individual and group interventions for weight loss, based on preference. Our 2009 systematic review compared long-term effectiveness of individual or group approaches to the same intervention, but there are new randomized controlled trials (RCTs) of high-quality data. We updated and expanded our previous systematic review. We searched Medline and Embase from 1966 to May 2021, and a clinical trial register from 1966 to 2017. Review Manager (5.4.1) was used to conduct meta-analysis. Ten RCTs were included. The primary outcome, mean weight change at final follow-up, was -1.33 kg (95% confidence interval CI: -2.04, -0.62; 10 trials, 2169 participants), favouring group interventions (p < .001). For the secondary outcomes, attainment of ≥5% body weight loss at final follow-up, the risk ratio (RR) was 1.36 (95% CI 1.05, 1.77; three trials, 1520 participants), favouring group interventions (p = .02); attrition at final follow-up was similar between group and individual arms of trials, RR 0.93 (95% CI 0.82, 1.07) (p = .31). Group interventions can be more effective than individual interventions for long-term weight loss in adults with obesity. However, few studies were included in the clinically relevant, secondary outcome measures. Research on delivering group processes in weight management is needed.