Feeding rats a diet super high in fructose for 4 months doesn’t really hurt their liver overall, even though a few tiny signs of fat buildup show up under a microscope.

Feeding rats a diet super high in fat leads to fat building up in their livers after 16 weeks — kind of like what happens in fatty liver disease. Scientists saw this through lab tests, scans, and looking at liver tissue under a microscope.

In lab rats, eating a diet super high in fructose (like from sugary foods) makes their blood fat levels skyrocket—way more than other unhealthy diets—and this seems to mess up how their body handles fat overall, not just hurt the liver.

Eating too many carbs and calories — especially from sugary or processed foods — is what mainly causes fatty liver, not eating fat. Cutting out carbs or going on a carnivore diet might help reverse it.

In mice, eating a super high-fat, very low-carb diet causes fat to build up quickly in the liver — way more than with other diets — which could be harmful.

When people eat a lot of fructose (like in sugary drinks), their liver has a harder time burning fat for energy, especially if they're also eating a lot of fat — which can lead to fat building up in the liver.