I have gotten comments from a number of readers on my passing comment on high-fructose corn syrup ("HFCS") in my
prior posting on soft drinks and obesity. I am not an expert on this particular aspect of the debate--I just noted the point to express my acknowledgement that the THEORY soft drink consumption might lead to increased obesity seems plausible, and the focus of my post was on whether there is empirical support for the argument (which I argued that there was not). I stand by the latter point, but have gotten several interesting comments that I thought were worth elaborating on the scientific point.
In the
update to that post I noted the clarification offered by FROG of the physiology of HFCS metabolism and his questions about the science.
Joe Hicks has alerted me to some other sources that discuss the science that underlies the hypothesis that HFCS can lead to obesity. The first is the
article that I had read that prompted my recognition of the theory in the first place. It is by Bray, Nielsen, and Popkin from the American Society for Clinical Nutrition. I was going to post the abstract, but it is extremely technical (the article itself contains some useful graphs that lay out the theory and evidence in an accessible way).
A less technical discussion is also provided on Dr. Joseph Mercola's web site, "
Six Reasons Why Corn Is Making You Fat."
As I said, I have no dog in this hunt, as the data appears to me that soft drink consumption has been constant for the past 15 years and my understanding is that the formula for soft drinks has been basically constant over that time. On the other hand, HFCS has been added to a large number of other foods during that period, as noted by Bray, Nielsen, and Popkin, so if the effect is large enough it could play some role in rising obesity. They observe in the article, "HFCS has become a favorite substitute for sucrose in carbonated beverages, baked goods, canned fruits, jams and jellies, and dairy products."
In my mind hard to believe that increased HFCS explains the whole rise in obesity, however. First, increased obesity is a worldwide phenomenon, so the HFCS model would have to be generalizable. Second, there has been a dramatic increase in the obesity of dogs and cats in the United States at about the same rate as people (estimates are that some 25-40% of American dogs are overweight or obese), and I'm pretty sure they aren't drinking too much Coke!
On the other hand, let me stress that it might still be appropriate to ban vending machines at school, although it will do little to combat obesity. I think a strong argument can be made that the problem with vending machines is that they permit children to consume junk food without parental supervision and on that basis alone it might be appropriate to ban them. It is probably time to do something about the terrible state of the school lunch program, which seems to be a nutritional disaster (but I'll leave it to someone else to sort that out).
Also, it should be noted (as many readers observed as well) that the initial impetus for the substitution to HFCS was the United States' ridiculous sugar agriculture policies, which jacked up the price of sugar so much as to force a substitution to corn sweetners in soft drinks in the first place (although I understand that HFCS is also more chemically stable as well, which explains part of the substitution, especially for processed bake goods).
Thanks to both Matthew Malewski and Joe Hicks for all this great info.