"You’ve read the headlines: America’s problem with bulging waistlines has reached pandemic proportions, according to federal health officials, who warn that obesity is becoming society’s No. 1 killer," wrote Michael S. Rosenwald, who by his own admission is 60-80 pounds over the limit.
One reported health concern is that if you eat too much HFCS, you increase your risk of having more health problems. I found many references to an investigation at the USDA, led by Dr. Meira Field, that noted when large amounts of sugar is fed to rats, surprise: the rats develop many different health problems. The USDA team then looked at both fructose and glucose to see which of the two ingredients may be contributing to the increases in health problems. The team fed two groups of rats the sugars, one group of rats getting glucose and the other fructose. It turned out that the glucose group was unaffected but the fructose group suffered a number of health problems.
In the mid nineties, research by Dr. Forrest Nielsen of the USDA’s Human Nutrition Research Center in Grand Forks found that fructose interferes with absorption of copper, which is needed in the creation of hemoglobin in the body’s red blood cells. Related to the test, the Center ran a study with a small test group with a diet of 20% fructose. The study found that the group’s total cholesterol and LDL cholesterol shot up.
As noted in the Chronicle, "the theory goes like this: The body processes the fructose in high fructose corn syrup differently than it does old-fashioned cane or beet sugar, which in turn alters the way metabolic-regulating hormones function. It also forces the liver to kick more fat out into the bloodstream. The end result is that our bodies are essentially tricked into wanting to eat more and at the same time, we are storing more fat."
Dr. Gabe Mirkin noted on his web site that "Recent data shows that large amounts of fructose cause insulin resistance, impair glucose tolerance, produce high levels of insulin, raise triglycerides, and cause high blood pressure in animals. Not all this data have been replicated in humans, but there is every reason to believe that large amounts of fructose will have the same adverse effects. High-fructose corn syrup is found in almost all soft drinks and fruit beverages and a wide variety of processed foods; check the list of ingredients in the foods you buy."
(The Washington Post ran an article in 2003 which may be of interest.)
Overall, I found the information on the wiki is great, providing a balance of results, and the views of nutritionists overall support the conclusion that the old saying is true: watch what you eat. (And never eat anything bigger than a bowling ball, at least in one sitting. OK, I made that up.)
High fructose corn syrup is often cited by some nutritionists as one of the leading causes of obesity and is linked to diabetes. The average American consumed 62.6 pounds (28.4 kilograms) of high fructose corn syrup in 2001, most of which came from soft drinks.
Some nutritionists and natural food advocates believe that consumption of high fructose corn syrup should be avoided due to its possible links with obesity and diabetes. Also cited as reasons to avoid HFCS are that it is highly refined, that it might be produced from genetically modified corn, that various molds found on corn might leave harmful byproducts in the final product, or that corn products in general should be avoided. ,  Other nutritionists say that HFCS is no more or less harmful than other forms of sugar and that all sugars should be consumed sparingly.
Of course, it’s not just HFCS that causes obesity – it’s a number of factors as the author in this week’s Post article notes. At home, we have taken steps to all but eliminate HFCS from the foods we buy for our family, but a few instances creep into our diets, primarily in some of the sugary sweets the kids like. But in the chocolate and ice cream we buy, we look for cane sugar and other alternatives. In sodas and juices, we look for "sweetened with natural juices."
But more importantly, we control portion sizes and apply moderation to our eating: no 64 ounce Big Gulps, ‘though a once-in-a-while treat are Slurpees for the kids. And we try to do more with our kids, most recently playing a family game of racket ball. Today, rain or shine, we’ll get them out for a walk or a playtime at the park. And we won’t be sitting on the benches.
“America: Drowning in Sugar” http://cspinet.org/new/sugar.html