New real-world data reveals bariatric surgery leads to five times greater weight loss than popular GLP-1 drugs like Ozempic and Zepbound over two years. This significant finding, presented at the ASMBS 2025 Annual Scientific Meeting, highlights a considerable gap in effectiveness for patients pursuing substantial and lasting weight reduction.
The study, conducted by researchers at NYU Langone Health and NYC Health + Hospitals, analyzed electronic medical records from over 50,000 patients with a BMI of at least 35. It directly compared outcomes for individuals undergoing sleeve gastrectomy or gastric bypass with those prescribed injectable semaglutide or tirzepatide.
After two years, bariatric surgery patients achieved an average weight loss of 58 pounds, translating to 24% of their total body weight. This outcome significantly surpasses the results seen with pharmacological interventions.
In stark contrast, patients relying on GLP-1 medications for at least six months lost approximately 12 pounds, representing just 4.7% of their total weight. Even those maintaining GLP-1 therapy for a full year saw average weight loss of only 7%, as reported by ScienceDaily.com.
Real-world challenges for GLP-1 weight loss drugs
The study’s findings highlight a critical divergence between controlled clinical trial results and real-world outcomes for GLP-1 drugs. Clinical trials often show weight loss between 15% to 21% for these medications. However, everyday use presents significant obstacles that temper these impressive figures.
Dr. Avery Brown, a surgical resident at NYU Langone Health and lead author, noted, “Clinical trials show weight loss between 15% to 21% for GLP-1s, but this study suggests that weight loss in the real world is considerably lower even for patients who have active prescriptions for an entire year.”
High rates of treatment discontinuation largely explain this gap. Research indicates that as many as 70% of patients may stop GLP-1 therapy within one year, with this figure rising to 72.2% after two years. Factors like side effects, out-of-pocket costs, and the need for long-term adherence often contribute to these challenges. Further insights into metabolic health can be found from the National Institutes of Health (NIH).
The overlooked potential of bariatric surgery
While GLP-1 drugs have garnered widespread attention, with about 12% of Americans having used them at some point, bariatric surgery remains a significantly underutilized option for long-term weight management. Despite its proven efficacy, only about 1% of eligible individuals undergo metabolic and bariatric procedures annually.
Dr. Ann M. Rogers, President of the ASMBS, who was not involved in the study, emphasized, “While both patient groups lose weight, metabolic and bariatric surgery is much more effective and durable.” She suggests that patients experiencing insufficient weight loss or compliance issues with GLP-1s should consider surgical alternatives.
The latest data from the ASMBS indicates over 270,000 bariatric procedures were performed in 2023. This figure, though substantial, barely scratches the surface of the population that could benefit, highlighting a significant disparity in treatment uptake. The American Society for Metabolic and Bariatric Surgery provides further insights into these trends.
The compelling real-world evidence underscores that for many individuals struggling with severe obesity, bariatric surgery offers a far more effective and durable solution than current GLP-1 medications. While these drugs play a role, their real-world outcomes often fall short of expectations due to adherence challenges.
Future research, as highlighted by Dr. Karan R. Chhabra, a bariatric surgeon and senior author, will aim to optimize GLP-1 outcomes and identify which patients are better suited for surgery versus medication. Ultimately, this ongoing investigation will help refine treatment decisions, ensuring patients receive the most effective interventions for sustainable weight loss and improved health. For general information on obesity and related health concerns, consult the Centers for Disease Control and Prevention (CDC).
