Bariatric surgery is more effective and durable than new drugs for obesity and lifestyle changes

Systematic reviews of the medical literature from 2020 to 2024 show that bariatric surgery, also known as metabolic or weight loss surgery, provides the greatest and most sustained reductions weight compared to GLP-1 receptor agonists and lifestyle changes. The research was presented today at the 2024 American Society for Metabolic and Bariatric Surgery (ASMBS) Annual Scientific Meeting.

The researchers found that lifestyle interventions such as diet and exercise resulted in an average weight loss of 7.4%, but that weight was usually regained within 4.1 years. GLP-1 and metabolic and bariatric surgery were significantly more effective. The studies included thousands of patients from clinical trials and several randomized clinical trials.

Five months of weekly injections of GLP-1 semaglutide resulted in 10.6% weight loss, while nine months of treatment with tirzepatide resulted in 21.1% weight loss. However, after stopping treatment, about half of the weight lost was regained within a year, regardless of the drug used. With continued injections, patients taking tirzepatide reached a plateau at 22.5% weight loss after 17 to 18 months. Patients on semaglutide reached a plateau of 14.9% over the same period.

Metabolic and bariatric surgery procedures such as gastric bypass and sleeve gastrectomy demonstrated overall weight loss of 31.9% and 29.5% at one year post-surgery, respectively. Weight loss of approximately 25% was maintained for up to 10 years post-surgery.

“Metabolic and bariatric surgery remains the most effective and durable treatment for severe obesity. Unfortunately, it also remains one of the least used,” said study co-author and bariatric surgeon Marina Kurian, MD, of NYU Langone Health. “Surgery should play a larger role in the treatment of obesity and be considered earlier in the disease process. It is no longer a treatment of last resort and should not be delayed until more severe forms of the disease have developed. There is no medical basis for this.”

“While new drugs show great promise and will lead to more people being successfully treated, especially if prices come down and insurance coverage improves, we are underutilizing the best tool we have to fight obesity — metabolic and bariatric surgery, which is safer and more effective than ever,” said Anne Rogers, MD, president-elect of ASMBS and professor of surgery at the University of Pennsylvania College of Medicine, who was not involved in the study. “For many people, the risk of dying from obesity, diabetes, and heart disease outweighs the risks of surgery.”

The study included a systematic review of studies examining weight loss using lifestyle interventions, GLP-1 (semaglutide or tirzepatide), or metabolic and bariatric surgery. The data on GLP-1 included four randomized clinical trials conducted between 2021 and 2024, while the findings on lifestyle modifications were based on a systematic review of eight studies. Metabolic and bariatric surgery (gastrobypass and sleeve gastrectomy) were the subject of a review of 35 studies, including two randomized clinical trials. In total, the researchers looked at the weight loss results of approximately 20,000 patients.