Study shows weight returns 4 times faster in GLP-1 drug users

People who use GLP-1 weight-loss drugs regain weight faster than those who lose weight through a traditional approach of diet and physical activity, a new study shows.

The findings are based on an observational meta-analysis published in the British Medical Journal, which covers 37 studies involving over 9,000 adults and evaluates how quickly weight returns after stopping obesity treatment medications.

The study examines both older therapies such as orlistat, which prevents the absorption of dietary fats, and highly popular ones like Novo Nordisk’s Wegovy containing semaglutide and Eli Lilly’s Mounjaro or Zepbound containing tirzepatide.

The general conclusion drawn by scientists is that patients can lose up to one-fifth of their body weight when using injectable GLP-1 drugs, but after stopping treatment, they regain it at an average rate of 0.8 kilograms per month. This means that the initial weight can be reached again in only about 18 months.

For all medications, the average rate of weight regain is 0.4 kilograms per month, the authors state. This is up to four times faster compared to people who lose weight through behavioral weight control programs, where the increase is about 0.1 kilograms per month and takes an average of about four years.

Secondary benefits of drug treatment, such as improvements in blood pressure and cholesterol levels, are also lost and return to baseline values within a year and 4 months.

According to Dr. Susan Jebb of Oxford University, the analysis shows that weight regain after stopping medication is common and occurs rapidly. She adds that cardiometabolic benefits directly follow changes in weight, and as weight increases, these benefits are lost.

One reason for the rapid weight regain is the fact that GLP-1 drugs allow for significant initial weight loss, as well as the high rate of treatment discontinuation. The authors also point out that behavioral methods encourage lifestyle changes that are often maintained even when weight begins to return.

Experts comment that the results support the intuitive understanding that relying solely on medication without lifestyle changes is not sufficient for long-term results.

Dr. Adam Collins, a nutrition expert at the University of Surrey who was not involved in the study, notes that prolonged artificial maintenance of GLP-1 levels significantly higher than normal can lead to reduced endogenous production of this hormone and lower sensitivity to its effects. According to him, after stopping this external control, appetite is no longer effectively suppressed and the risk of overeating increases sharply, especially if the person has relied entirely on the weight-loss medication. He emphasizes that the main message of the study is that drugs make weight loss easier, but maintaining the achieved weight becomes an even greater challenge.

Professor Naveed Sattar of the University of Glasgow points out that the study cannot assess whether short-term use of these drugs brings lasting benefits, but considers it possible that even two to three years at a lower weight could help delay damage to joints, the heart, and kidneys.