by Cheryl Critchley,Monash University

Credit: Ketut Subiyanto from Pexels

Combining bariatric surgery with weight loss medication can help people who need to lose more weight post-surgery, Monash University and Alfred Health-led research has found.

The paper ispublishedin the journalJAMA Network Open.

Around 31% of Australian adults live with obesity. Metabolic Bariatric Surgery (MBS) is the most effective and durable treatment, with most patients losing 20–30 % of their total body weight. However,10–15%do not have an optimal weight loss, or they regain weight after the operation.

It is not possible to predict who these people will be prior to surgery, and the only option to induce further weight loss has been more surgery, which carries a risk of serious complication that is 4–5 times higher.

Given effective medications can also induce weight loss, the study was designed to see if it was possible to safely combine surgery with obesity management medications (OMM).

The work used the OMM liraglutide, originally developed to manage type 2 diabetes, on patients with poor results following metabolicbariatric surgery. The double-blinded randomized controlled trial involving 48 adults saw half take daily liraglutide and the other half take a placebo.

At 12 months, the liraglutide group had a mean total body weight loss (TBWL) of 4.4 % compared to an increase of 1.4 % in thecontrol group—a significant difference.

There were no adverse impacts on health or quality of life.

First author Professor Wendy Brown, who heads the Monash University Department of Surgery and is The Alfred's Oesophago-Gastric-Bariatric Unit Director, said the results were promising.

"We have shown that for people who regain weight or don't have an optimal weight loss effect from bariatric surgery, adding in a weight loss drug will help them to lose weight, often at a lower dose than is needed in people who have not had surgery," Professor Brown said.

"We are the first to show that the full dose of obesity management medication may not be needed in the post-bariatric surgery setting, and importantly, quality of life is not affected by introducing the obesity management medication. This raises the possibility of avoiding risky repeat surgery, which is the current main option when people need more weight loss after bariatric surgery."

Study participants were aged 20–65, and 12–36 months post-procedure, including adjustable gastric band (AGB),sleeve gastrectomy, roux-en-y gastric bypass and one anastomosisgastric bypass.

The 48 eligible patients with sub-optimal surgery results were randomized, with 24 self-administering liraglutide daily over 12 months and the other 24 taking a placebo.

"Liraglutide provided greater weight loss at 12 months than placebo in a cohort of patients with a sub-optimal response to MBS," the researchers found.

Joint senior author Professor John Wentworth, an adult endocrinologist at the Royal Melbourne Hospital, said the results were exciting.

"Our demonstration that incretin drugs enhance weight loss following bariatric surgery provides great hope," Professor Wentworth said. "Excitingly, newer, more effective drugs have become available and should help our patients achieve even better weight and health outcomes."

Co-author Adjunct Associate Professor Dr. Paul Burton, from the Monash University School of Translational Medicine's Department of Surgery, and The Alfred's Oesophago-Gastric and Bariatric Unit, said MBS enabled durable weight loss, improved a range of obesity-associated diseases and increased life expectancy.

However, he said up to 15 % of patients experienced suboptimal weight loss and therefore less improvement in health outcomes.

"A multimodal approach has long been the guiding principle in care following weight loss surgery, but until now rested on a limited evidence base," Dr. Burton said. "The results reinforce that personalized treatment, careful patient selection, sustained lifestyle change, and ongoing adherence are essential to managing obesity as a lifelong disease we can remit but not cure.

"There are no quick fixes, but we now have increasingly effective, evidence-based treatment options. These findings support a personalized, long-term strategy that pairs surgical expertise with medication, lifestyle support, and ongoing engagement to achieve durable remission rather than a cure."

Liraglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist, which has been studied in three previous randomized controlled trials exploring combined medication and surgery.

They also resulted in varying degrees of weight loss, suggesting a role for medications for sub-optimal weight loss after surgery.

"Combining therapies might also enable less effective yet safer and reversible procedures, such as AGB, to be re-considered as a viable option," the study found.

DOI and link to paper:10.1001/jamanetworkopen.2025.39848

More information: Wendy A. Brown et al, Liraglutide and Weight Loss Among Suboptimal Responders to Metabolic Bariatric Surgery, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2025.39848 Journal information: JAMA Network Open

Provided by Monash University