Stars like Oprah Winfrey have been celebrating their success with weight-loss drugs, but stopping the medication could lead to the kilos quickly piling back, researchers warn.

New science published in The British Medical Journal (BMJ) shows that people on drugs like Wegovy regained weight four times faster than those on diet and exercise programs.

All the lost weight was likely to be regained surprisingly soon — in less than two years, at the rate of about 400 grams per month.

Risk markers for diabetes and heart disease were also predicted to return to pre-treatment levels in less than two years.

And the beneficial effects of weight loss on cholesterol and blood pressure were also reversed.

“This evidence suggests that despite their success in achieving initial weight loss, these drugs alone may not be sufficient for long-term weight control,” said the researchers.

The findings cast doubt on the notion that GLP-1 receptor agonists, which are in demand around the world, are a perfect cure for obesity.

Around half a million Australians are believed to be using GLP-1 drugs like Ozempic and Wegovy, either for weight loss or other health reasons.

The injections are also used to treat type 2 diabetes, and right now are only subsidised under the Pharmaceutical Benefits Scheme (PBS) to treat that condition.

The Australian government is considering subsidies for the medications, which could be listed on the PBS.

A University of NSW report found around half of people taking the drugs buy them privately for between $200 and $600 a month.

Australia’s medicines regulator warned recently that Ozempic-style drugs could cause suicidal thoughts and behaviours, urging caution among patients who take them.

Weight-loss drugs are injected, but a Wegovy pill has been launched in the United States.

It is estimated that around half of people with obesity stop their GLP-1 drugs within 12 months.

What happens after the treatment has been the subject of much anecdotal discussion that researchers are wanting to understand.

To do this, a team from the University of Oxford looked at studies comparing the effects of drug-induced weight loss with traditional methods or placebo.

Thirty-seven studies, published up to February 2025 involving 9341 participants, were included in the analysis.

The average duration of weight-loss treatment was 39 weeks, with an average follow-up of 32 weeks.

Participants treated with weight-loss drugs regained on average 400 grams per month after stopping treatment and were projected to return to their pre-treatment weight by 1.7 years.

All cardio-metabolic risk markers were projected to return to pre-treatment levels within 1.4 years after stopping the drugs.

Monthly weight regain was also faster after weight-loss drugs than after behavioural weight management programmes (by 0.3kg), independent of initial weight loss.

“This evidence cautions against short-term use of weight management medications, emphasises the need for further research into cost-effective strategies for long-term weight control, and reinforces the importance of primary prevention,” said the authors.

The authors acknowledged several limitations. For example, only eight studies assessed treatment with the newer GLP-1 drugs and the maximum follow-up period in these studies was 12 months after medication stopped.

Oprah Winfrey ‘more alive’

Former talkshow host Oprah Winfrey started using weight-loss medication two and a half years ago and says GLP-1 has transformed her life.

Winfrey told People: “I thought it was about discipline and willpower. But I stopped blaming myself.

“I feel more alive and more vibrant than I’ve ever been.

“I’m not constantly punishing myself. I hardly recognise the woman I’ve become. But she’s a happy woman.”

By contrast, Winfrey previously felt “embarrassed” by her appearance.

She explained: “I’ve always been confident in whatever I was doing, but I was at the same time disappointed in my overweight body.

“Was I embarrassed by it? Yes. Was I disappointed in myself for continuing to fail? Yes, every single time. I felt it was my fault.”

–with AAP