They are half fructose and half glucose similar to the structure of sucrose (table sugar).
HFCS is NOT the problem, high consumption of sugar in general is the problem.
"Epidemiological studies show growing evidence that consumption of sweetened beverages (containing either sucrose or a mixture of glucose and fructose) is associated with a high energy intake, increased body weight, and the occurrence of metabolic and cardiovascular disorders. There is, however, no unequivocal evidence that fructose intake at moderate doses is directly related with adverse metabolic effects. There has also been much concern that consumption of free fructose, as provided in high fructose corn syrup, may cause more adverse effects than consumption of fructose consumed with sucrose. There is, however, no direct evidence for more serious metabolic consequences of high fructose corn syrup versus sucrose consumption."
"If you see a product with HFCS and a similar product with natural table sugar, don’t assume the product with natural sugar is any better. Rather than worrying about whether something contains HFCS, you should strive to reduce your intake of all types of added sugar and refined carbohydrates in your diet. It is much more important to look at the big picture; keep your physical activity high, manage your overall food intake, make sure most of your food is from minimally refined sources, and keep your protein intake high. This is what will help you lose weight and keep it off, rather than singling out HFCS in your diet. Don’t let the fructose fear-mongerers fool you"
Agave, a more "natural" sugar actually contains more fructose than HFCS
Increased food energy supply (alone) is more than sufficient to explain the US epidemic of obesity
It would take an absurd amount of say, fruit, to provide enough fructose to the diet to cause problems. The liver can generally handle approximately 50 grams of fructose or so before you start to see conversion to triglycerides or other negatives. Only achievable by someone consuming a lot of sugary soda, but again, anyone consuming gallons of sugary soda per day has bigger issues in their diet than the high fructose intake.
HFCS is in no way unique amount sugars, with a composition identical to sucrose as well as the supposedly ‘healthy’ honey. Increased caloric intake since the 1970′s is the driver for increased obesity, with no relationship with HFCS intake per se. In that all fructose-glucose solutions (whether HFCS, sucrose or honey) are metabolized in exactly the same fashion in the body, there is simply no reason to think that HFCS per se is particularly obesity promoting outside of being a caloric source.
In terms of sweetener comparison, table sugar and HFCS are very, very similar. Only reason HFCS sells is because it's cheaper to make. The human body does not metabolise HFCS any differently to regular sugar.
