Researchers at Joslin Diabetes Center have found that high levels of fructose in the diet inhibit the liver’s ability to properly metabolize fat. This effect is specific to fructose. Indeed, equally high levels of glucose in the diet actually improve the fat-burning function of the liver. This explains why high dietary fructose has more negative health impacts than glucose does, even though they have the same caloric content.

High-fructose and high-fat diet damages liver mitochondria: Increases fatty-liver disease risk and metabolic syndrome — ScienceDaily