They could also be affecting our metabolism, gut bacteria and appetite, say researchers from the University of Manitoba.
The researchers took another look at 37 studies that had tracked the health of more than 400,000 people as they used sweeteners. The people weren't losing weight, and the longer studies—which were observing the participants for up to 10 years—noted that they were instead putting on the pounds, and they were more likely to be obese, have high blood pressure, diabetes, heart disease and other health issues compared to others who weren't using sweeteners.
Although millions use sweeteners every day, it's astonishing that very little research has been carried out into their safety, or even their supposed ability to help keep weight down, says lead researcher Ryan Zarychanski.
At the very least, the jury's out, say the researchers, and people should be using sweeteners with caution, or even not at all, until more research has been carried out.
In the meantime, the researchers are going to look at the impact artificial sweeteners may have on the unborn child when the mother uses them when she's pregnant.