If you think you're avoiding artificial sweeteners because you don't put them in your coffee or tea, think again. These additives are found in everything from yogurt and baked goods to sauces and diet colas, per the CBC, with "a lot of people ... consuming them in foods and not realizing it," says University of Manitoba researcher Meghan Azad. Azad, the co-author of a new study published Monday in the Canadian Medical Association Journal, also notes that 40% of adults report using artificial sweeteners on a regular basis—which may prove pointless when it comes to dropping pounds, as her team has found no evidence that the sweeteners help with weight loss and may even cause other health issues. Azad's team conducted a meta analysis of 37 previously published studies of the diets of nearly 407,000 people, only seven of which were randomized control trials.
"A lot of the studies we found were observational, meaning they could show a link, but they can't prove a cause-and-effect relationship," she tells CTV News. Among the seven more-rigorous trials, regular consumption of artificial sweeteners had no significant effect on weight loss, while among the 30 observational studies, regular consumption was tied to a higher risk of Type 2 diabetes and high blood pressure, as well as "modest" weight gain. Possible reasons for the weight gain, per Azad: Our bodies may metabolize based on sweetness perception (not sugar content), gut bacteria affected by sweeteners may affect obesity, or we may give ourselves permission to eat more sweets after eating diet products. An internal medicine expert says the studies aren't clear enough to cast all blame on artificial sweeteners; Azad says there isn't enough evidence the sweeteners are "truly harmless." (When it comes to higher blood sugar, gut bacteria may play a role.)