The safety of sugar substitutes is a separate issue from whether they aid in weight loss. And it’s likely that they will always be controversial, since research linking various sugar substitutes to cancer, cardiovascular disease, or other health problems periodically makes headlines, and since rumors about them, even debunked ones, never seem to die.
For instance, an Italian study caused a stir in 2016 when it reported that sucralose caused cancer in mice. Subsequently, the Center for Science in the Public Interest, which a few years before had changed sucralose’s status from “safe” to “caution,” further demoted the artificial sweetener to its “avoid” category.
The study had a number of problems, however. For one, what happens in lab animals doesn’t necessarily happen in humans. And the researchers did not explain why only the male mice developed more cancers (other reported data were also ambiguous). In addition, the amount of sucralose used in the study, adjusted for body weight, far exceeded the amounts that a person could possibly consume (as is true of most other studies that have tested artificial sweeteners in animals). And keep in mind that this was just one study, compared to the 110 studies upon which sucralose’s approval for safety was based.
Though research continues into the safety of sugar substitutes, the National Cancer Institute has stated that saccharin, aspartame, acesulfame K, and sucralose are safe. The 2015 Dietary Guidelines Advisory Committee Report examined only the evidence for aspartame and concluded that it appears to be safe at the levels normally consumed. But because there have been only a few studies that looked at the safety of these sweeteners in children, the American Academy of Pediatrics has issued no official recommendations regarding their use.
Bottom line: With a few caveats, the available evidence suggests that sugar substitutes are safe overall. Still, moderation is a good idea, especially in children, since possible adverse effects from chronic intake over the long term have not definitively been ruled out. What’s more, if you find yourself using a lot of sugar substitutes, it might mean your diet, on the whole, is on the unhealthy side and could use some improvement.
It’s one thing to use a packet or two in your coffee or tea or to eat an occasional “sugar-free” treat, but another to be consuming artificially sweetened foods all day long, since these tend to be highly processed “junk” foods like “sugar-free” puddings, ice cream, and soft drinks. After all, sugar substitutes are not an ingredient in healthy whole foods, like whole grains, legumes, and fresh fruits and vegetables—the types of foods that should make up the bulk of your diet.