In theory, artificial sweeteners offer consumers the promise of sweet without the extra calories. In the U.S., a quarter of children and 41 percent of adults report eating artificial sweeteners like aspartame, sucralose and stevia. But a scientific review of 37 studies on non-nutritive sweeteners, published Monday in the Canadian Medical Association Journal, found that there is no evidence to suggest sweeteners help in weight management.
"We were really interested in the everyday person who is consuming these products not to lose weight, but because they think it's the healthier choice, for many years on end," Meghan Azad, lead author of the review and an assistant professor in the department of pediatrics and child health at the University of Manitoba in Canada, tells NPR.
The studies in the review varied — seven were randomized controlled trials (the ideal in the scientific community) and the rest were observational. Together, they followed more than 400,000 individuals for roughly a decade. The review concluded, based on the studies, that artificial sweeteners don't help people lose weight.
"I think there's an assumption that when there are zero calories, there is zero harm," Azad tells TIME. "This research has made me appreciate that there's more to it than calories alone."
The observational studies, which followed people for a longer period of time, saw an association with regular consumption and a higher risk of obesity, diabetes, high blood pressure, and heart disease. But the link is not confirmed, as observational studies do not prove cause and effect. Translation: Just because those who regularly eat sweeteners have more health issues doesn't mean sweeteners are causing it. When it comes to dietary habits, it is especially unclear. It could be, for instance, that people who use more sweeteners tend to eat more processed foods.
The Calorie Control Council, a trade group representing the low- and reduced-calorie food and beverage industry, is calling out the study's design saying it "took a broad approach."
"Low-calorie sweeteners are a tool to help provide sweet taste without calories to address one aspect of calorie intake," Robert Rankin, president of the Calorie Control Council, says in a statement. "Taste preferences are an important component of dietary habits, but successful weight management requires a well-rounded strategy.
Azad, who has replaced her usual Splenda with milk, notes that more research needs to be done.
"Caution is warranted until the long-term health effects of artificial sweeteners are fully characterized," Azad says in a statement. "Given the widespread and increasing use of artificial sweeteners, and the current epidemic of obesity and related diseases, more research is needed to determine the long-term risks and benefits of these products."