A surgeon in an operating room looks at a monitorShare on Pinterest
Surgeons say bariatric surgery is the most effective method for weight loss management. Daniel Gonzalez/Stocksy
  • Researchers say weight loss surgery is the best option for losing and sustaining weight loss.
  • GLP-1 drugs such as Ozempic and Wegovy help people lose weight, but the researchers said weight often returns when people stop taking the medications.
  • Researchers reported that 10 years after bariatric surgery, many people still weighed 25% less than before their operation.

Compared to GLP-1 medications such as Ozempic and Wegovy, bariatric surgery provides the most significant and most sustained weight loss, according to a study presented at the American Society for Metabolic and Bariatric Surgery’s 2024 Annual Scientific Meeting.

For their findings, which haven’t been published yet in a peer-reviewed journal, researchers completed systematic reviews of studies published between 2020 and 2024.

They reported that bariatric surgery, also called metabolic or weight-loss surgery, provided better results — both in terms of weight loss and sustained time — than GLP-1 agonists.

The scientists reviewed studies that included thousands of people from clinical studies and several randomized clinical trials. They reported that lifestyle interventions, including diet and exercise, resulted in an average weight loss of 7% of body weight. However, they reported that people typically regained the weight within about 4 years.

They said that GLP-1 medications and weight loss surgery were superior to lifestyle interventions.

“Diet and exercise do not work for the vast majority of people,” said Dr. Christine Ren-Fielding, the chief of bariatric surgery at NYU Langone Health and surgical director of NYU Langone’s Weight Management Program in New York.

Genetic makeup is often to blame,” Ren-Fielding, who was not involved in the study, told Medical News Today. “The perception of people who are obese is that they are lazy and don’t care. That usually isn’t true. They need options other than diet and exercise.”

The researchers studied a number of treatments for obesity.

They reported that 20 weeks of weekly injections of GLP-1 semaglutide (Ozempic, Wegovy) resulted in a 10% body weight loss and 36 weeks of weekly injections of tirzepatide (Mounjaro, Zepbound) resulted in a 21% body weight loss.

They also reported that:

  • Once treatment stopped, about one-half of the weight returned for both drugs.
  • If treatment was continued, a weight loss plateau of 22% for tirzepatide and about 15% for semaglutide was reached after 17 to 18 months.

When looking at the results of weight loss surgery, the researchers found a total weight loss of nearly 32% for gastric bypass and 29% for sleeve gastrectomy one year after surgery. Study participants maintained weight loss of about 25% up to 10 years after surgery.

“Metabolic and bariatric surgery are the most effective and durable treatment for obesity, said Dr. Mir Ali, a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in California.

“Diet and exercise are only effective for 1 to 2 percent of people who are obese,” Ali, who was not involved in the study, told Medical News Today. “Not only is it the most effective for weight loss, but it is also the most effective for sustaining weight loss. Surgery is very underutilized, with only about 1 to 2 percent of people who could benefit from it getting the surgery. These surgeries have long-term benefits with remissions lasting 15 years or more.”

Another expert agrees with Ali’s assessment.

“The best therapy for metabolic syndrome and type 2 diabetes remains surgery,” said Dr. Mitchell Roslin, the chief of bariatric surgery at Northwell Lenox Hill Hospital in New York. “The results are lasting as the control mechanism is part of you.”

“In comparison, the GLP medicines have half as much weight loss in diabetics, as those without,” Roslin, who wasn’t involved in the study, told Medical News Today. “Stated differently, these medications have been approved for diabetes for approximately 10 years. Numbers have only increased and few have had lasting weight loss similar to these studies.”

“Too few people are educated about surgery,” Roslin added. “My comment would be that medical therapy keeps you from dying, but surgical procedures probably keep you from aging as fast.”

However, experts note that lifestyle changes are important, even with surgery.

“No matter how a person chooses to lose weight, diet, exercise, and lifestyle changes are still essential to maintain weight loss,” said Anne Danahy, a registered dietician and nutritionist who was not involved in the study.

“Bariatric surgery has the potential for the most significant and longest-lasting weight loss, but because it alters your digestive tract and limits what and how much you can eat, it also requires a commitment to permanent diet and lifestyle changes,” she told Medical News Today. “Without those long-term changes, it’s very possible to regain much of the weight after the surgery.”

GLP-1 agonists such as Ozempic and Wegovy are used to treat obesity and diabetes.

They work by lowering glucose levels and managing hunger. The medications are typically injectables, with many taken once a week. Semaglutide is available as a daily tablet.

“I think the GLP-1 medications are more in demand right now,” Ali said. “They offer a weight loss solution that is lower risk than surgery. For some people with underlying medical conditions, surgery is not an option, and the medications provide an alternative.”

Insurance coverage can be an issue. Most companies require a BMI [body mass index] of 30 without other medical conditions and a BMI of 27 if other medical conditions are present,” Ali added. “Some insurance companies do not cover the medications and if someone is paying out of pocket, they can cost $1,000 or more per month.”

Another issue is that people can gain half their weight back when they stop taking the medications.

“The medications control hunger and when they are stopped, the hunger returns,” Fielding said. “Think blood pressure medications. Your blood pressure is controlled while you are taking the medications and as soon as you stop, your blood pressure goes up.”

“These medications are wonderful and very effective if you want to lose 30 pounds,” Ren-Fielding said. “But if you want to lose 100 pounds, they aren’t as effective. Surgery is the best option in those cases.”

With so many choices, picking the best option can be difficult.

“Determining the best weight loss strategy — bariatric surgery, diet and lifestyle changes, or a GLP-1 drug, like semaglutide or tirzepatide — depends on your health conditions, weight loss goals, and health history,” said Tatiana Ridley, a wellness expert, holistic nutritionist, and health coach who was not involved in the study.

“Some clients in our Medical Weight Loss Program at ReBalance NYC require weight loss before undergoing bariatric surgery. To help them achieve their pre-surgery goals, we integrate diet and lifestyle plans, often with GLP-1 medications,” she told Medical News Today.

Ridley lists several things to consider when selecting a weight loss plan:

  1. Consult a healthcare professional for a medical evaluation and discuss your weight loss goals, preferences, and any questions you have about different treatment options.
  2. Consider Your BMI and overall health.While BMI measurements can provide a fast and simple method to assess health outcomes, it overlooks various factors such as demographic differences, body weight distribution, and body fat percentage.
  3. Evaluate treatment efficacy, potential drawbacks, and sustainability

“Considering these factors and working with healthcare professionals, you can determine the most appropriate and effective weight loss strategy for your needs,” Ridley said.

According to the World Health Organization, obesity is a chronic disease characterized by excessive fat deposits that can impair health.

The condition can lead to type 2 diabetes and heart disease, increase the risk of some cancers, affect bone health and reproduction, and negatively influence the quality of life. It can also cause inflammation and weaken the immune system.

Obesity is measured using BMI. For adults, a BMI equal to or greater than 25 is considered overweight. A measurement equal to or greater than 30 is considered obese.

The researchers noted that the U.S. Centers for Disease Control and Prevention (CDC) reports that obesity affects 42% of people living in the United States.