By Dr Joe Milton, the Australian Science Media Centre

An international study published this week found that people who stop taking weight-loss medications often see their hard-won progress slip away fast.

GLP‑1 weight‑loss medications such as Ozempic and Wegovy have been hailed as game-changers in the fight against obesity, and the study found they're very effective, while patients are still taking them.

Unfortunately, the researchers say most people regained the weight they lost when they stopped taking these drugs, often in less than two years. That's roughly four times faster than after diet and exercise programs.

Laureate Professor Clare Collins from the University of Newcastle and the Hunter Medical Research Institute, who was not involved in the study, told the AusSMC the research team had "pooled the results from 37 individual studies that compared the rate of weight regain in adults who had been taking various medications for weight management with people in control groups who had either received a lifestyle intervention or no intervention at all".

That allowed them to look at data from more than 9,300 people.

The results don't reflect a failure of the drugs, according to Prof Collins, but "highlight that obesity is a chronic relapsing condition with health and medical implications”.

On average, people on the medications regained about 0.4 kg per month, with many returning to their starting weight in under 18 months. That was around 0.3 kg more per month than people on dietary weight loss programmes.

That means "these medications will need to be taken long-term (just like other health conditions)”, said Prof Collins.

Dr Trevor Steward from the University of Melbourne told the Centre the study "confirms what many patients and clinicians have experienced in the real world".

So, it seems medication alone isn't enough.

"The new obesity management medications have greatly improved efficacy, but do not cure the disease of disordered energy balance,” said Adjunct Professor John Dixon from Swinburne University of Technology.

So, exactly why is it so hard to keep the weight off?

"Changes to hunger-regulating hormones are very long-lasting. We got evidence all the way to three years,” Emeritus Professor Joseph Proietto from the University of Melbourne told the Centre.

And a study of participants in 'The Biggest Loser' TV show found hunger-suppressing hormone levels were still very low six years after losing weight, he said.

"This means that the patients must stay on the hunger-suppressing hormones for the rest of their lives."

Another potential solution is to combine weight loss drugs with other strategies, according to Professor Garron Dodd from the University of Melbourne.

"Sustainable treatment will likely require combination approaches, longer-term strategies, and therapies that reshape how the brain interprets energy balance, not just how much people eat," he told the AusSMC.

“GLP‑1 drugs have changed the conversation… but this new data makes it clear they are a starting point, not a cure."

You can read the EXPERT REACTION in full here

This article originally appeared in Science Deadline, a weekly newsletter from the AusSMC. You are free to republish this story, in full, with appropriate credit.

Contact: Dr Joe Milton

Phone: +61 8 7120 8666

Email: info@smc.org.au