Behavioral weight management interventions in metabolic and bariatric surgery: A systematic review and meta-analysis investigating optimal delivery timing.

Metabolic and bariatric surgery (MBS) yields unprecedented clinical outcomes, though variability is high in weight change and health benefits. Behavioral weight management (BWM) interventions may optimize MBS outcomes. However, there is a lack of an evidence base to inform their use in practice, particularly regarding optimal delivery timing. This paper evaluated the efficacy of BWM conducted pre- versus post- versus pre- and post-MBS. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and included pre- and/or post-operative BWM interventions in adults reporting anthropometric and/or body composition data. Thirty-six studies (2,919 participants) were included. Post-operative BWM yielded greater decreases in weight (standardized mean difference [SMD] = -0.41; 95% confidence interval [CI]: -0.766 to -0.049, p < 0.05; I = 93.5%) and body mass index (SMD = -0.60; 95% CI: -0.913 to -0.289, p < 0.001; I = 87.8%) relative to comparators. There was no effect of BWM delivered pre- or joint pre- and post-operatively. The risk of selection and performance bias was generally high. Delivering BWM after MBS appears to confer the most benefits on weight, though there was high variability in study characteristics and risk of bias across trials. This provides insight into the type of support that should be considered post-operatively.