EDIT2: (now that I've watched the whole lecture) Already covered by inglor_cz, but for posterity, the first EDIT is incorrect - in addition to quantity problem

EDIT2: (now that I've watched the whole lecture) Already covered by inglor_cz, but for posterity, the first EDIT is incorrect - in addition to quantity problems, Fructose and Glucose are processed very differently in the liver. Fructose impact on the liver is much more like Alcohol than Glucose.