Obesity (Silver Spring)Weight LossMeta-AnalysisDecember 1, 2025

Comparative Efficacy of Metabolic/Bariatric Surgery Versus GLP-1 Receptor Agonists: A Network Meta-Analysis of Randomized Controlled Trials.

Sabatella L, Ortega PM, Azcárate VV, Sastre FR, Pagola AU, Ahmed A, Purkayastha S, Ojanguren CT, Asensio NB, Landecho MF

View on PubMed DOI: 10.1002/oby.70100

Key Finding

Bariatric surgery beats GLP-1 drugs for weight loss by an extra 10.3% of total body weight at 2 years, though the gap narrows to just 9.1% - except tirzepatide performs so well it's statistically tied with surgery.

What This Study Found

Think of this study like a massive boxing tournament between weight loss champions, analyzing 30 fights with over 20,000 participants. In one corner: bariatric surgery (the heavyweight champion), in the other: GLP-1 medications (the rising contender). The researchers didn't pit them directly against each other, but instead compared how each performed against the same opponent - lifestyle changes alone - then calculated who would win head-to-head. At the 2-year bell, surgery was still the clear winner, delivering an average of 10.3% more total weight loss than GLP-1 drugs. For a 200-pound person, that's like surgery helping them lose an extra 20 pounds compared to medication. Surgery also dominated in shrinking waist size (12.6 cm more), dropping BMI (4.5 points more), and improving diabetes control. But here's the plot twist: when they looked specifically at tirzepatide (the newest dual-hormone drug), it fought surgery to essentially a draw - the differences weren't statistically significant, meaning they could just be due to chance.

Statistics Decoded

The p-values tell us these differences probably weren't just luck: p=0.001 for weight loss difference is like flipping heads 1,000 times in a row. The -10.3% weight loss difference means if GLP-1s help you lose 15% of your weight, surgery would help you lose 25.3%. The BMI difference of -4.5 kg/m² is substantial - that's moving from 'severely obese' well into 'moderately obese' territory. At 104+ weeks (2+ years), the weight gap stayed meaningful at -9.1% and -14.6 kg actual weight difference, with p=0.022 and p=0.049 respectively - still probably not due to chance, though less certain than the shorter-term results.

Why This Matters

This gives patients and doctors a clear roadmap: surgery remains the gold standard for major weight loss, but tirzepatide has emerged as the first non-surgical option that can realistically compete, potentially sparing some patients from going under the knife while still achieving life-changing results.

Original Abstract

This study compared the efficacy of metabolic/bariatric surgery (MBS) and GLP-1 receptor agonists (GLP-1 RAs), including dual GLP-1/GIP analogues, for weight and metabolic outcomes in adults with obesity. A network meta-analysis of randomized controlled trials compared MBS or GLP-1 RAs versus lifestyle intervention in adults with overweight or obesity. Primary outcomes were percent total weight loss (TWL) and BMI; secondary outcomes included body weight, waist circumference, HbA1c, and systolic blood pressure. Random-effects models used lifestyle intervention as the common comparator; all MBS versus GLP-1 RA comparisons were indirect. Thirty randomized controlled trials (n = 20,015) were included. At < 104 weeks, MBS achieved greater reductions than GLP-1 RAs in %TWL (ETD -10.3%; p = 0.001), BMI (-4.5 kg/m2; p < 0.001), body weight (-11.7 kg; p < 0.001), waist circumference (-12.6 cm; p < 0.001), and HbA1c (-0.5%; p = 0.033). At ≥ 104 weeks, differences remained for %TWL (-9.1%; p = 0.022) and body weight (-14.6 kg; p = 0.049). In tirzepatide-only analyses, differences versus MBS were not significant. Among participants with type 2 diabetes, MBS produced greater reductions in BMI, weight, waist, and %TWL, with similar HbA1c improvement. Both MBS and GLP-1 RAs provide substantial metabolic benefits. MBS remains superior, but tirzepatide is a promising nonsurgical option supporting personalized obesity care.