I've been curious for a while now about the proven differences—or lack thereof—between current boogeything high-fructose corn syrup and sugars, in general. I haven't had a chance to do any heavy reporting on the subject, but, the more of other people's reporting I read, the less worried I am about the stuff. Here's a few of the key things I'm learning:
1) Diets high in sugars—all and any kinds of sugars—are bad for you. If high-fructose corn syrup is a bigger problem than other sweeteners, it's because the stuff is so cheap that it enabled food companies to add delicious, delicious sweetener to all kinds of things that might not otherwise have contained it. But that's a function of economics, not chemistry. In fact, high-fructose corn syrup isn't the only "added sugar" in use. It makes up about half the added sugars in processed foods. The others—beet sugar, cane sugar, etc.—still rack up calories and are still no good.
2) Sugary beverages are a key factor in rising obesity rates. They happen to be sweetened, usually, with high-fructose corn syrup. But, again, that's because it's the cheapest sweetener. It's probably not the specific sweetener that's the problem here, but the fact that Americans drink a lot of sugary beverages. We'd be seeing a problem from over-consumption even if the sweetener was sugar.
3) The few studies that have turned up evidence for corn-syrup specific weight gain have had inconsistent results. Other studies have demonstrated potential health problems linked to consumption of fructose compared to other forms of sugar—but fructose isn't something that's specific to high-fructose corn syrup. In fact, high-fructose corn syrup has less fructose than a lot of other sweeteners. We only call it "high-fructose" because it's got a higher fructose-to-glucose ratio than straight-up corn syrup.
4) One of the sweeteners that has way more fructose than high-fructose corn syrup: Agave nectar. It's somewhere between 70% and 87% fructose, while most of the high-fructose corn syrup you'll run into is only 55% fructose. Other natural sweeteners, like honey and apple sugar, are also in the range of around 50% fructose. There's no solid evidence that shows this fructose to be any different than the fructose in high-fructose corn syrup. If you're really concerned about fructose (And I'm not sure you should be yet. Most of those studies are dealing with pure fructose in test tube or animal research, not real-life mixtures of sugar in human bodies.) your best bet may be maple syrup, which is only 1% fructose.
My take: Keep an eye out for added sugars—of all kinds—in products. If you're worried about empty calories and weight gain, that's your real concern. But don't stress too much about this. Cutting down on the added sugars in your life is good. But a little added sugar isn't going to kill you. And high-fructose corn syrup isn't more of a worry than any other sweetener.
Where am I getting this from?
Science Based Medicine: Corn Syrup: Tasty Toxin or Slandered Sweetener?
New York Times "Well" Blog: In Worries About Sweeteners, Think of All Sugars
Slate: Dark Sugar
The Journal of Nutrition: The State of Science on Dietary Sweeteners Containing Fructose: Summary and Issues to Be Resolved
American Medical Association: REPORT 3 OF THE COUNCIL ON SCIENCE AND PUBLIC HEALTH—The Health Effects of High Fructose Syrup, Executive Summary (PDF)
Junkfood Science: The Science of Sweets