PARIS: When people stop taking the new generation of weight-loss drugs, they pile on the pounds four times faster than they would after ending diet and exercise regimens, new research found Thursday.
But it was mostly due to the fact that they lost so much weight in the first place, believe the British researchers, who have produced the largest and most up-to-date review of the subject.
A new generation of appetite-suppressing, injectable drugs called GLP-1 agonists have become hugely popular in the last few years, changing the treatment of obesity and diabetes in many countries.
They have been shown to help people lose between 15% to 20% of their body weight.
“It all seems to be good news,” said Susan Jebb, a public health nutrition researcher at Oxford University and co-author of a new BMJ study.
However, recent data have suggested that “about half of people stop taking these medications within a year,” she told a news conference.
This could be because of common side effects such as nausea or the cost – these drugs can cost over $1,000 a month in the US.
So the researchers reviewed 37 studies that looked at stopping various weight loss medications and found that participants gained about 0.4 kg per month.
Six of the clinical trials involved semaglutide – the ingredient used in Novo Nordisk’s brands Ozempic and Wegovy – and tirzepatid used in Eli Lilly’s Mounjaro and Zepbound.
While taking these two drugs, the subjects lost an average of almost 15 kg.
However, after stopping the medication, they gained 10 kg within a year, which was the longest follow-up period available for these relatively new drugs.
The researchers expected the participants to return to their original weight in 18 months.
Measures of heart health, including blood pressure and cholesterol levels, also returned to their original levels after 1.4 years.
People who were instead put on programs that included diet and exercise — but not drugs — lost significantly less weight. But it took an average of four years for them to regain their lost kilos.
This meant that people who took the drugs gained weight four times faster.
‘Starting point, not a cure’
“Greater weight loss tends to result in faster weight regain,” explained lead study author Sam West of Oxford University.
But separate analysis showed that weight gain was “consistently faster after medication, regardless of the amount of initial weight loss,” he added.
This may be because people who have learned to eat more healthily and exercise more often continue to do so, even if they gain weight.
Jebb emphasized that GLP-1 drugs “are a really valuable tool in obesity treatment — but obesity is a chronic relapsing condition.”
“One would expect these treatments to be continued for life, similar to blood pressure medications,” Jebb said.
If this were the case, it would affect how national health systems assess whether these drugs are cost-effective, the researchers stressed.
“These new data make it clear that they are a starting point, not a cure,” said Garron Dodd, a metabolic neuroscientist at the University of Melbourne who was not involved in the study.
“Sustainable treatment will likely require combination approaches, long-term strategies and therapies that reshape how the brain interprets energy balance, not just how much people eat,” he said.
