People who already have health issues like obesity or diabetes often switch to artificial sweeteners to help manage their condition—so when studies see that sweetener users have worse health, it might not be because the sweeteners caused the problem, but because people with the problem chose the sweeteners.

People who drink diet sodas or use artificial sweeteners often have health problems, but it might not be because the sweeteners cause the problems — maybe people who are already unhealthy are just more likely to use them.

If you swap out sugary drinks like soda for diet drinks with artificial sweeteners, studies suggest you might be less likely to get type 2 diabetes, heart disease, or die from heart problems or any cause — but only if the study makes sure people weren’t already sick when they switched drinks.

Artificial sweeteners might be bad for your health in the long run, so we should use them carefully, know what we're eating, have stricter rules, and do more studies to figure out how to stay safe.

Using sugar substitutes like stevia or aspartame doesn’t make you more likely to have bad health effects than eating sugar, drinking water, or taking a fake pill—so they’re probably safe if you’re trying to lose weight.