A new study from New York University (NYU) reveals that bariatric surgery—specifically sleeve gastrectomy and gastric bypass—is five times more effective than prescription weight loss drugs like Ozempic (semaglutide) and tirzepatide over a two-year period. The findings, presented at the American Society for Metabolic and Bariatric Surgery (ASMBS) annual meeting in June 2025, highlight a significant disparity in real-world weight loss outcomes.
The Study’s Findings: A Clear Difference
Researchers compared health records of patients undergoing bariatric surgery with those taking GLP-1 receptor agonists, matching participants based on age, body mass index (BMI), and blood sugar levels. The results were striking: surgical patients lost an average of 25.7% of their total body weight within two years, while those on medication lost only 5.3%. Even over shorter time frames, surgery consistently yielded superior results.
This difference isn’t solely due to patient compliance. While adherence to GLP-1 drugs is often inconsistent—with up to 70% of patients discontinuing treatment within a year—the study also observed better outcomes from surgery even when accounting for adherence.
Why This Matters: The Rise of GLP-1s and Surgical Alternatives
The findings come at a time when GLP-1 medications are exploding in popularity, with prescriptions doubling between 2022 and 2023. These drugs mimic the natural GLP-1 hormone, controlling appetite and aiding weight loss. However, the study suggests that real-world weight loss with GLP-1s is often lower than clinical trial results, even for those who remain on prescriptions for an entire year.
The effectiveness gap is important because weight loss is increasingly linked to broader health benefits. Bariatric surgery, in this study, also demonstrated superior blood sugar control compared to GLP-1s. While Ozempic and similar drugs were initially approved for type 2 diabetes—and have shown promise in reducing cancer and cardiovascular risks—surgery appears to provide more durable metabolic improvements.
Considerations: Surgery Isn’t a Quick Fix
It’s crucial to note that surgery isn’t without its drawbacks. These procedures are invasive, permanent, and still require patients to maintain strict diet and exercise regimens for long-term success. The study was funded by ASMBS, an organization with a clear stake in promoting surgical options, which warrants consideration when interpreting the results.
Researchers acknowledge that GLP-1 drugs still offer benefits, but advocate for realistic expectations and improved adherence or, alternatively, consideration of metabolic and bariatric surgery to achieve desired weight loss results.
“While both patient groups lose weight, metabolic and bariatric surgery is much more effective and durable,” said ASMBS President Ann M. Rogers.
Future research will focus on optimizing GLP-1 outcomes, identifying which patients benefit most from surgery versus medication, and addressing cost barriers to treatment success. For now, the study underscores a critical point: when it comes to significant, lasting weight loss, bariatric surgery remains the gold standard.
