INTRODUCTION: Metabolic and bariatric surgery (MBS) and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are both effective strategies for obesity management, but their comparative efficacy remains uncertain. This systematic review and meta-analysis aimed to compare weight loss outcomes between MBS and GLP-1 RA therapy in adults with obesity.
METHODS: A systematic search of PubMed, Scopus, and Cochrane Library was conducted from inception to September 22, 2025. Eligible studies included randomized and observational comparisons between MBS-specifically sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB)-and GLP-1 RA therapy in adults with obesity. Pooled mean differences (MDs) for total weight loss (TWL) and body mass index (BMI) change were calculated using a DerSimonian-Laird random-effects model. Risk of bias was assessed using ROBINS-I V2, and certainty of evidence was graded with GRADE.
RESULTS: Five retrospective observational studies (n = 5,944; 3,489 MBS, 2,455 GLP-1 RA) met the inclusion criteria. Pooled analysis showed significantly greater TWL in the MBS group (MD - 18.15%; 95% CI 16.41 to 19.90; p < 0.0001; I² = 95%) and larger BMI reduction (MD 8.73 kg/m²; 95% CI 5.87 to 11.58; p = 0.0001; I² = 94.6%). Sensitivity analyses confirmed the robustness of these results. Overall risk of bias was moderate, primarily due to non-randomized designs and treatment selection bias. Certainty of evidence was rated as moderate.
CONCLUSIONS: MBS achieves significantly greater and more durable weight loss compared with GLP-1 RA therapy, reaffirming its role as the most effective intervention for severe obesity. While GLP-1 RAs represent valuable noninvasive or adjunctive options, surgery remains the benchmark for sustained metabolic and weight outcomes.
