In rats, eating a diet high in fat and low in carbs changes how the liver handles certain fuels — it makes more sugar from lactate but gets worse at using alanine, especially when fewer calories are eaten.

When rats eat a diet high in fat and low in carbs, their livers start making more sugar from lactate but get worse at breaking down an amino acid called alanine — especially if they're also eating fewer calories.

Even when rats eat fewer calories, a keto-like diet can still cause liver problems — like making too much sugar and messing up how the body uses protein — so the weight loss might not be worth the harm.

Even when rats eat fewer calories, a keto-like diet can still cause unhealthy changes in the liver, like making too much sugar and having trouble breaking down proteins.

Eating fewer carbs might make your liver produce more sugar, and some scientists think this could put extra strain on your liver.

Rats on a very low-carb, high-fat diet for a month ended up with higher blood sugar and more fat in their livers—even if they didn’t eat more calories. This kind of diet might not be great for liver and blood sugar health in animals.