SAN DIEGO-Bariatric surgery far outperforms lifestyle interventions and glucagon-like peptide-1 (GLP-1) medications at maintaining weight loss, according to a meta-analysis presented at the 2024 annual meeting of the American Society for Metabolic and Bariatric Surgery.

With results from six randomized controlled trials, three systematic reviews, and more than 40,000 patients, the study is the first synthesis of its kind.

“The analysis included two systematic reviews of bariatric surgery, one of Roux-en-Y gastric bypass including8,665 patients and one of sleeve gastrectomy including 6,095 patients: a single systematic review or lifestyle interventions including 723 patients; and six randomized controlled trials of GLP-1 medications, including four studies of semaglutide with a total of 11,871 patients and two of tirzepatide with 3,209 patients.

Lifestyle interventions were the least effective treatment, the investigators found, producing a mean total body weight loss of 7.4% at the end of the treatment period, followed by a mean per-month weight regain of 0.14%, with participants reaching their pre-intervention weights within 4.1 years.

GLP-1 medications proved more effective. Weekly semaglutide injections for 20 weeks and tirzepatide for 36 weeks produced a mean total body weight loss of 10.6% and 21.1%, respectively. Roughly half of the weight lost was regained within a year after stopping injections; with continued injections, weight loss plateaued after 17 to 18 months, at 14.9% for semaglutide and 22.5% for tirzepatide.

Outcomes after surgery were significantly better. Gastric bypass surgery and sleeve gastrectomy resulted in a mean total body weight loss of 31.9% and 29.5%, respectively, one year after surgery. Accounting for weight regained in the decade after surgery, both procedures produced a stable total body weight loss of approximately 25%.

While the results demonstrate a striking difference favoring surgery, lead investigator Megan Jenkins, MD, a bariatric surgeon at NYU Langone Medical Center in New York City, emphasized that surgery and medication ought to be viewed not in opposition but through a holistic lens as options and potential complements based on the needs of each patient.

“One of the big benefits of these new medications is that it’s helped us to treat obesity as a chronic disease,” Dr. Jenkins said. “We’ve always treated it that way, but I think the medical field has had trouble truly seeing it as a chronic disease. Like diabetes and high blood pressure, for example, which have always been treated with a combination approach.