UPDATE after the jump. A new study by the University of California indicates that high fructose corn syrup could be just as unhealthy as some nutrition experts have thought.
In short, the first tests conducted on humans showed that subjects who were fed a diet high in fructose accumulated fat cells around their vital organs -- and they showed early signs of diseases like diabetes. A separate group ate a diet sweetened with sugar and showed no such signs.
The study also showed that fructose jumps directly to the liver without being digested like a normal sugar. Of course this leads to all kinds of metabolic problems, the most obvious being obesity.