High Fructose Corn Syrup
Is
not a natural carbohydrate and, unsurprisingly, the human body is
not equipped to deal with it in the same way it deals with carbohydrates which our bodies and our ancestors' bodies have been processing for a very long time.
The industry has done a brilliant job of putting out lies that it is "just sugar" which is a bit like saying cancer is "just extra cells", all natural, all yours.
I am not going to jump on the all hfcs is bad bandwagon, but the ratio of sugars is not one which our bodies copes with properly and there are now several independent studies done by real scientist, not the usual kooks, to confirm it.
The second link contains a more balanced review for normal people like me.
It will probably turn out that small amounts of the stuff are not dangerous, but we consume quantities which are way too high for our own good.
And that's the problem in the end: The dose makes the poison.