Study shows how quickly weight comes back after stopping weight loss drugs

PARIS: When people stop taking the new generation of weight-loss drugs, they pile on the pounds four times faster than they would after stopping diet and exercise, new research showed Thursday.

But that’s mainly because they lost so much weight in the first place, according to British researchers who conducted the largest and most up-to-date review on the subject.

A new generation of injectable appetite-suppressing drugs called GLP-1 agonists have become wildly popular in recent years, transforming obesity and diabetes treatment in many countries.

They have been found to help people lose 15% to 20% of their body weight.

“This all seems to be good news,” said Susan Jebb, a public health nutritionist at the University of Oxford and co-author of a new BMJ study.

However, recent data suggest that “about half of people stop these drugs within a year,” he told a news conference.

This may be due to common side effects such as nausea or the price—these drugs can cost over $1,000 a month in the US.

So researchers looked at 37 studies that involved stopping different weight-loss drugs, finding that participants regained about 0.4 pounds per month.

Six of the clinical trials involved semaglutide – the ingredient used in Novo Nordisk’s brands Ozempic and Wegovy – and tirzepatide used in Eli Lilly’s Mounjaro and Zepbound.

While taking these two drugs, trial participants lost an average of nearly 15 pounds.

However, after stopping the medication, they regained 10 pounds within a year, which was the longest follow-up period available for these relatively new drugs.

The researchers predicted that the participants would return to their original weight in 18 months.

Measures of heart health, including blood pressure and cholesterol levels, also returned to baseline after 1.4 years.

People who instead put on programs that included diet and exercise — but no drugs — lost significantly less weight. However, it took an average of four years for them to regain their lost weight.

This meant that people taking the drugs regained their weight four times faster.

“A starting point, not a cure”

“Greater weight loss tends to result in faster weight regain,” explained study lead author Sam West of the University of Oxford.

However, a separate analysis showed that weight gain was “consistently faster after medication, regardless of the amount of weight initially lost,” he added.

This could be because people who have learned to eat healthier and exercise more often continue to do so even when they regain weight.

Jebb emphasized that GLP-1 drugs “are a really valuable tool in the treatment of obesity — but obesity is a chronic relapsing condition.”

“One would expect that these treatments should be continued for life, just like blood pressure medications,” Jebb said.

If this were to happen, it would have an impact on how national health systems judge whether these drugs are cost-effective, the researchers pointed out.

“These new data make it clear that they are a starting point, not a cure,” said Garron Dodd, a metabolic neuroscience researcher at the University of Melbourne who was not involved in the study.

“Sustainable treatment will likely require combination approaches, longer-term strategies and treatments that reshape how the brain interprets energy balance, not just how much people eat,” he said.