Can the sweetener acesulfame-K in sugar-free foods cause fatty liver?

What's actually in it

Acesulfame potassium (often called Ace-K) is one of the most common artificial sweeteners in sugar-free products. You'll find it in diet sodas, sugar-free gum, low-calorie yogurt, protein shakes, and "zero sugar" snack bars. It's about 200 times sweeter than regular sugar and adds no calories.

Food makers often blend it with other sweeteners like sucralose or aspartame. Check the label on most "sugar-free" or "light" products in your kitchen, and there's a good chance Ace-K is listed.

What the research says

A 2026 study in Int J Mol Med looked at how acesulfame-K affects liver cells. The researchers found it triggers a chain reaction through a receptor called PPARa that controls how your liver handles fat.

When Ace-K activates this pathway, liver cells start storing more fat than normal. Over time, that extra fat buildup can lead to non-alcoholic fatty liver disease (NAFLD). The study traced the exact steps: Ace-K flips on a liver enzyme called PLCb, which then scrambles the signals that normally keep fat storage in check.

The tricky part is that PPARa usually protects the liver. But the study found that Ace-K pushes this receptor into a harmful mode instead. It's like turning a guard into an attacker.

This was a lab study, not a human trial. But it gives a clear picture of how a "zero calorie" sweetener could still cause problems in your body. If you use a lot of sugar-free products daily, it's worth paying attention to which sweeteners are in them.