Due to the way the body processes fructose and glucose, fructose leads more directly to being 'fat', as it's stored as adipose tissue more readily/rapidly than glucose. Fructose, in HFCS and other solutions, is becoming extremely common in food where it did not used to be - this is leading to the huge increase in metabolic syndrome/etc. tl;dr: sugar makes you fat, but different sugars do it at different rates.