PARIS (Reuters) – When people stop taking the new generation of weight-loss drugs, they pack back the pounds four times faster than they would after finishing diet and exercise regimens, new research found on Thursday.
But this was mainly because they lost a lot of weight in the first place, according to British researchers who conducted the most extensive and up-to-date review on the subject.
A new generation of injectable appetite suppressant drugs called GLP-1 agonists has become immensely popular in recent years, transforming the treatment of obesity and diabetes 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 nutrition scientist at the University of Oxford and co-author of a new BMJ study.
However, recent data has suggested that “about half of people stop these medications within a year,” he said at a news conference.
This could be due to common side effects such as nausea or the price: these medications can cost more than $1,000 a month in the United States.
So, researchers reviewed 37 studies looking at quitting different weight-loss medications and found that participants regained about 0.4 kilograms per month.
Six of the clinical trials involved semaglutide, the ingredient used in Novo Nordisk’s Ozempic and Wegovy brands, and tirzepatide used in Eli Lilly’s Mounjaro and Zepbound.
While taking these two medications, trial participants lost an average of almost 15 kilograms.
However, after stopping the medication, they regained 10 kilograms within a year, which was the longest follow-up period available for these relatively new medications.
The researchers projected that participants would return to their original weight within 18 months.
Measurements of heart health, including blood pressure and cholesterol levels, also returned to their original levels after 1.4 years.
People who instead followed programs that included diet and exercise, but not medications, lost significantly less weight. However, it took them an average of four years to regain the lost kilos.
This meant that people taking the drugs regained their weight four times faster.
‘Starting point, not a cure’
“Greater weight loss tends to result in faster weight regain,” explained the study’s lead author, Sam West, of the University of Oxford.
But a separate analysis showed that weight gain was “consistently faster after medication, regardless of the amount of weight lost in the first place,” 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.”
“You would expect that these treatments would have to be continued for life, just like blood pressure medications,” Jebb said.
If this were the case, it would affect how national health systems judge whether these drugs are cost-effective, the researchers emphasized.
“These new data make it clear that this is 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 combined approaches, longer-term strategies, and therapies that reshape how the brain interprets energy balance, not just how much people eat,” he said.
