A new real-world study shows that people who have weight loss surgery lose much more weight than those who take injectable medications like semaglutide or tirzepatide.
The study found that, after two years, people who had bariatric surgery lost about five times more weight than those using these medications.
The research was presented at the 2025 Annual Scientific Meeting of the American Society for Metabolic and Bariatric Surgery (ASMBS). It was done by a team from NYU Langone Health and NYC Health + Hospitals.
The study followed patients for two years. On average, those who had surgery—either sleeve gastrectomy or gastric bypass—lost 58 pounds. That’s about 24% of their total body weight.
In comparison, people who took GLP-1 medications for at least six months lost only 12 pounds, or 4.7% of their weight. Even patients who stayed on the medication for a full year lost just 7%, still much less than the weight lost through surgery.
In clinical trials, GLP-1 drugs have been shown to help people lose 15% to 21% of their body weight. But this study showed that in real-world conditions, people tend to lose much less. One reason is that many people stop taking the medication.
About 70% of users stop within a year. The medications can have side effects and are expensive, making it hard for people to keep using them.
The researchers used data from over 51,000 patients treated between 2018 and 2024. All of the patients had a body mass index (BMI) of at least 35. Some had surgery, while others received prescriptions for semaglutide or tirzepatide. The researchers adjusted for factors like age and health conditions to make a fair comparison.
The study was supported by a grant from the National Institutes of Health (NIH). The researchers hope to do more studies in the future to understand how to improve the results of GLP-1 treatment. They also want to learn which patients do better with surgery and how money and insurance coverage affect treatment success.
GLP-1 drugs have become very popular. About 12% of Americans have tried one, and 6% are currently using one. But sticking with the treatment is a problem. Research shows that more than half of users stop within a year, and over 70% stop within two years.
At the same time, weight loss surgery is still not widely used. In 2023, about 270,000 people in the U.S. had bariatric surgery, but that’s only 1% of the people who qualify based on their weight.
Experts say that while medications can help some people, surgery is much more effective for long-term weight loss. ASMBS President Dr. Ann Rogers said that people who don’t get the results they want from GLP-1 drugs—or who stop due to side effects or cost—should consider surgery instead. In some cases, surgery and medication may even be used together.
Obesity continues to be a major health issue in the U.S. According to the Centers for Disease Control and Prevention (CDC), more than 40% of American adults are obese, and nearly 10% have severe obesity. Obesity can weaken the immune system, cause ongoing inflammation, and increase the risk of heart disease, stroke, type 2 diabetes, and certain cancers.
This study suggests that for many people struggling with obesity, bariatric surgery may offer a more powerful and lasting solution than medication alone. Patients should talk with their doctors about the best treatment plan for their personal health and lifestyle needs.
If you care about weight loss, please read studies about orange that could help obesity, and a berry that can prevent cancer, diabetes and obesity.
For more health information, please see recent studies about ginger’s journey in weight management, and green tea: a cup of weight loss.
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