Here's one reason why I stay away from HFCS. When researchers do diabetes experiments on rats, in which they induce diabetes in order to see which drugs ease, treat, or reverse diabetes, what do they use to do it? HFCS. Common table sugar doesn't seem to work the same way. It's almost impossible to get the rats to eat enough plain sugar to cause acute diabetes, but with HFCS it happens in a very short time.
Think of the amount of HFCS hidden away in grocery products, at restaurants, in blended coffee syrups. We get far more fructose than our body can handle these days, when our ancestors got fructose only in the fruit they ate, and even then, the amount ingested by hunter-gatherer fruit fiends paled in comparison to the amount we have access to today.
I'd rather keep my fructose consumption to a minimum, so I skip out on anything with HFCS in it if I can help it.
1) eat real food - more vegetables, moderate meat, moderate fruits, less grains, less sugar, less vegetable oils.
2) exercise - moderate intensity cardio, sprinting, heavy lifting, dedicated stretching and mobility.
3) live - relax, de-stress, meditate.
Disclaimer: I'm not professionally qualified to make any formal recommendations. I've just done my homework and I'm my own guinea pig. All of my data, unless otherwise cited, comes from a sample size of n=1 (me).