Another piece I found which may be of interest:
A Princeton University research team has demonstrated that all sweeteners are not equal when it comes to weight gain: Rats with access to high-fructose corn syrup gained significantly more weight than those with access to table sugar, even when their overall caloric intake was the same.
In addition to causing significant weight gain in lab animals, long-term consumption of high-fructose corn syrup also led to abnormal increases in body fat, especially in the abdomen, and a rise in circulating blood fats called triglycerides.
Princeton University - A sweet problem: Princeton researchers find that high-fructose corn syrup prompts considerably more weight gain
It has to be taken in to account as well that Americans, in general, tend to consume more sugar now than they did years ago and it has been suggested on various internet sites that the consumption of sugar is around 10% of total calories in their diet; pretty sure some will be higher. Obviously, other countries will also have higher intakes of sugar because that's the way things have gone but I haven't read any stats for those.
HFCS, from what I read, is banned in the UK, or at least it was banned whether that has changed I have no idea but it's not an ingredient that I've come across in foods here; though, it could easily appear under a different name.