Weight-loss medications like Ozempic could speed up metabolism, study finds

Weight-loss medications such as Ozempic may not just suppress appetite but could also speed up metabolism and burn more calories, a study carried out in St Vincent’s University Hospital has found.
Those involved in the study say the findings challenge the belief that the medications simply cause those who take them to “eat less”, but also allow for the burning of more calories by speeding up metabolism.
A randomised controlled trial of 30 patients found that those who had low metabolic activity before starting treatment benefited the most from medications such as Ozempic, Wegovy and Monjaro.
The 30 patients involved had specialised imaging of the fat within their abdomen using a PET-CT scanner, with scans carried out before and after six months of treatment. The findings published in the Journal of the Obesity Society on Thursday show “a strong relationship” between the increase in metabolic activity caused by taking the medications once daily and the amount of weight lost.
Prof Donal O’Shea, who led the trial alongside UCD’s school of medicine, said the study challenges the narrative that these newer treatments “simply make you eat less, and that any action on energy burn is minimal”.
“The strength of the association is surprising given the relatively small numbers studied and suggests this increase in metabolic activity is a significant contributor to how these drugs work,” he said.
Mr O’Shea said the body’s biggest defence against weight loss is to turn down its energy burn, adding that the study is the first in humans to show that the medications not only stop that from happening but increase the body’s natural calorie-burning mechanism.
However, he said understanding how the medications do this should be an important part of future research, noting that safe medical treatment for obesity is “still in its infancy”.
“It always seemed over simplistic to me that these new treatments were just making people eat less. So this study finding is an exciting step forward in our understanding of how these new medicines for obesity work. The findings also provide science to support the fact that the treatment of obesity is not simply to eat less and move more – that’s the prevention piece – treatment is more complex than that.”