This is one that is more of concern in the US than the UK, where it is unusual for high fructose corn syrup (or HFCS) to be used. The reason it tends to be used in the US is that it is cheaper than conventional sugar, apart from anything else because fructose, one of the two sugars in HFCS (the other is glucose), is sweeter than sucrose (the fructose/glucose combo in conventional sugar). This means that technically it is slightly healthier than sucrose, as you can use less HFCS than cane or beet sugar to get the same sweetness.
There is nothing magic about any of these sugars, and HFCS has less fructose concentration than, say, an apple or pear. And, to be absolutely certain, there has been plenty of good research done on HFCS which shows that there are no negative effects whatsoever, apart from the usual problems of sugar.
So that's it. It's yet another scare because HCFS sounds less 'natural' than cane or beet sugar. In the end it's the same stuff, but because fructose is sweeter than sucrose, you need less of it to get the same level of sweetness, so if you have a choice, you should go for the HCFS. Like all sugars, it's something we should consume in moderation. Like all sugars, almost all of us should consume less. But the dire warnings doing the rounds on social media making it a dietary bogeyman have no basis whatsoever.
- Sugar - page 102