Is the increased use of high-fructose corn syrup responsible for the rise in obesity?
I just read the question in your online archive about whether Coca-Cola once contained cocaine, toward the end of which you mention the substitution years ago (before I was born, in fact) of high-fructose corn syrup (HFCS) for sugar in Coke. These days, HFCS is found in not just Coca-Cola but most sodas, candy, juices, sauces, ketchup, jelly, bread, yogurt, etc. — it's in everything. My boyfriend hates HFCS and goes out of his way to buy products that do not use it, which can be a bitch to find sometimes. His claims are twofold: one, that increased use of HFCS is a major factor in the obesity problem in this country, because it's processed differently by the body, and two, that increased use of HFCS is a result of pressure from corn growers. I am inclined to believe him. Certainly, trying to eliminate HFCS from my diet has improved the quality of the food I eat. But others remain unconvinced. Straight dope, please.
I'd love to back up your boyfriend on this one, because in my opinion Coke hasn't been the same since the company ditched sugar for corn syrup. However, let's examine the logic here: (1) Americans are way fatter than they used to be. (2) We're eating more and exercising less, two guaranteed ways to put on the pounds. (3) Ergo, the problem is an obscure difference in sugar chemistry. You don't need to be Socrates to realize this conclusion is a bit of a reach.
Rumblings about HFCS have been building for several years. In 2003 journalist Greg Critser published a book entitled Fat Land: How Americans Became the Fattest People in the World in which he suggested that fructose, and specifically HFCS, was a major contributor to obesity. A study appearing last April in the American Journal of Clinical Nutrition lent support to Critser's view. George Bray and associates noted that: (a) U.S. consumption of HFCS rose 1,000 percent between 1970 and 1990. (b) Americans' rate of obesity increased sharply during the same period. (Currently 31 percent of the citizenry is obese and 64 percent overweight, compared to 15 percent and 47 percent, respectively, in the late 1970s.) (c) Fructose affects the body differently from glucose, another common form of sugar — for one thing, it doesn't stimulate a rise in blood insulin levels (diabetics use it for that reason). The researchers speculated that people tend to use more HFCS because it doesn't trigger the "I'm full" hormonal response produced by traditional forms of sugar (e.g., cane sugar, known as sucrose).
I won't say HFCS has nothing to do with obesity. But to focus on the stuff when there are so many other plausible explanations for American rotundity seems perverse. For one thing, we're eating more in general. One study says our average daily food intake increased from about 1,800 calories in 1989-91 to 2,000 in 1994-96. Much of that is surely due to fizzy beverages. Per capita soft drink consumption has doubled since 1970; the typical American currently consumes 56 gallons per year.
Is that increase due strictly to the allure of HFCS? Not likely. Sales of diet pop have increased at an even faster rate than that of the sugared kind, suggesting that we're not just overdoing HFCS-sweetened foods, we're consuming too much sweetened everything. Supersized portions and changes in eating habits no doubt partly explain why — the percentage of food kids get from restaurants and fast-food outlets increased almost 300 percent between 1977 and 1996. Critser's book includes a graphic showing that the rise in U.S. obesity roughly paralleled the rate at which junk-food products were introduced. Lack of exercise is a factor too. Obesity is lowest among kids who watch an hour or less of TV daily, highest among those who watch four hours or more.
Whatever chemical differences there may be between fructose and glucose, the difference between HFCS and traditional sugar is slight. Both sweeteners contain both compounds, and in roughly similar amounts — table sugar is 50 percent fructose and 50 percent glucose, whereas the most common form of HFCS is 55 percent fructose and 45 percent glucose. For what it's worth, Michael Jacobson, executive director of the Center for Science in the Public Interest and a frequent critic of the food industry, dismisses contentions that HFCS is uniquely to blame for the fact that we're fat.
To your boyfriend's other point: Did corn growers bludgeon the food industry into switching to HFCS? Probably not. The corn processors, on the other hand … well, it's not as if these guys treat their customers gently. Archer Daniels Midland, a major HFCS producer, recently agreed to pay a $400 million fine for conspiring to fix the sweetener's price. But it's generally conceded that HFCS dominates the market for the simple reason that, notwithstanding occasional essays in market manipulation, it's cheap.