A new real-world study has found that bariatric surgery is significantly more effective than GLP-1 medications like semaglutide and tirzepatide for long-term weight loss. At the two-year mark, patients who underwent sleeve gastrectomy or gastric bypass lost an average of 58 pounds—nearly five times more than those who used GLP-1 drugs, who lost just 12 pounds on average.
The study, presented at the 2025 Annual Scientific Meeting of the American Society for Metabolic and Bariatric Surgery (ASMBS), involved a large patient population from NYU Langone Health and NYC Health + Hospitals.
All patients included had a body mass index (BMI) of at least 35, qualifying them for obesity treatment. Researchers analyzed data from over 51,000 patients who either received bariatric surgery or had an active prescription for GLP-1 injections between 2018 and 2024.
Even for GLP-1 users who stayed on the medications continuously for a full year, the results showed only a 7% total body weight loss—still far less than the 24% weight loss achieved by surgery patients. While clinical trials of GLP-1s have reported 15–21% weight loss, real-world outcomes appear to fall short, likely due to issues with adherence, side effects, or cost.
“GLP-1 patients may need to adjust their expectations, adhere more closely to treatment, or opt for bariatric surgery to achieve desired results,” said lead author Dr. Avery Brown, a surgical resident at NYU Langone. He pointed out that as many as 70% of patients stop taking GLP-1 drugs within the first year, a major factor in their limited long-term success.
Despite their proven effectiveness, bariatric procedures like sleeve gastrectomy and gastric bypass remain underused. In 2023, only about 270,000 metabolic and bariatric surgeries were performed in the U.S.—less than 1% of those who are eligible.
This is in stark contrast to the rising popularity of GLP-1 drugs, with 12% of Americans saying they have tried them and 6% currently using them. Yet a recent study found that over half of GLP-1 users discontinue treatment within a year, and nearly three-quarters stop within two years.
Dr. Karan Chhabra, senior author of the study and a bariatric surgeon at NYU Grossman School of Medicine, said future research will focus on identifying which patients are best suited for each type of treatment and how to improve success rates for GLP-1 users. This includes looking at the impact of out-of-pocket costs, which can be a major barrier to staying on these expensive medications.
ASMBS President Dr. Ann M. Rogers, who was not involved in the study, emphasized the value of surgery. “While both patient groups lose weight, metabolic and bariatric surgery is much more effective and durable,” she said.
“Those who get insufficient weight loss with GLP-1s or have challenges complying with treatment due to side effects or costs should consider bariatric surgery as an option—or even in combination.”
With obesity rates in the U.S. continuing to rise—currently affecting 40.3% of adults, including 9.4% with severe obesity—effective and sustainable weight loss solutions are critical. Obesity is known to increase the risk of many serious health issues, including heart disease, stroke, type 2 diabetes, and certain cancers.
This study adds to the growing evidence that while GLP-1 medications can be helpful for some patients, bariatric surgery remains the most powerful option for substantial and lasting weight loss—especially in the real world, where long-term medication adherence is a challenge.
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