High Fructose Corn Syrup: Hard Questions, Easy Answer

If you’ve read anything about obesity and nutrition in the past few years, or paid any attention to food packages in the supermarket, you’re aware that there’s a bit of a controversy surrounding a sweetener called high fructose corn syrup, or HFCS. By “a bit of a controversy,” I mean a continuously escalating shouting match involving two extreme, opposing views and a whole lot of ambiguous data.

In one corner, we have a few researchers and a lot of foodies who argue strenuously that HFCS is a major cause, if not the sole cause, of the global pandemic of obesity, diabetes, and “metabolic syndrome.” Opposing these advocates is a multi-billion-dollar government-subsidized food processing industry, heavily invested in producing HFCS-laden products, claiming that the stuff is completely harmless and safe. In between are a lot of scientists genuinely trying to figure out a knot of apparently conflicting study results. Meanwhile, the general public would really appreciate some clear answers before it’s time to serve dinner.

Biochemical conversion of fructose to glycogen.

Fructose, in its usual role of torturing biochemistry students while forming glycogen.

The underlying questions in this debate are very hard to unravel, but this is an unusual instance where most of us can simply disregard all of that and make a simple, obvious choice based on sound risk analysis. Here’s why.

The scientific evidence on HFCS is all over the map, contrary to what advocates on both sides would have you believe. There is no clear proof that this stuff is safe, and no clear proof that it isn’t. Instead, we have a whole lot of suggestive, circumstantial evidence that HFCS might be bad for you, and a whole lot of suggestive, circumstantial evidence that it might not. Many anti-HFCS advocates point to the timing of the sweetener’s introduction, as it became prevalent in the global food supply at exactly the same time we started porking up. On the other hand, the same period saw widespread adoption of cable TV and then the internet, a decline in manufacturing and rise in sedentary work in developed countries, a steady decrease in sleep, and so on. Trying to look at this in more detail, a team of scientists recently completed a huge analysis of multinational data sets, and found that nations with high HFCS consumption rates also have relatively high rates of obesity and metabolic syndrome, even when matched for other traits. However, HFCS consumption could simply be a surrogate marker for processed food consumption, and in any case this particular study doesn’t prove much.

Mechanistic analyses have been similarly ambiguous: feeding rats a diet rich in HFCS can cause them to gain weight, but rodent metabolism differs radically from human metabolism. The most rigorous studies in humans have involved isocaloric diets with either HFCS or sugar as the primary sweetener, and found no difference in weight gain. Isocaloric diets are misleading, though. Outside of controlled clinical trials people eat until they’re full, and there are sound biochemical reasons to believe that our satiety circuits may not register the excess fructose in HFCS the same way we register the breakdown products of sucrose. If HFCS-laden food makes you feel less full for a given number of calories, it could prompt you to eat more. But that’s just a theory.

These mud-clear data haven’t stopped some folks from taking strong stances on the issue. I’ve even been guilty of overinterpreting studies that agreed with my preconceived notions at the time, and my wife is entirely sold on the idea that HFCS is liquid evil. More broadly, authors of papers like the new multinational analysis haven’t shied away from hype-enriched press releases, and of course the deep-pocketed industry making the product is guilty of exactly the same behavior. Both sides repeat their mantras (“It’s nutritionally equivalent to sugar,” “Is not,” “Is so…”) while ignoring all evidence to the contrary. The stakes are astronomical, so the screaming is quite loud.

As I said, though, there’s a very easy way out of this discussion. HFCS contains no essential nutrients. It occurs in no staple foods. It is completely unnecessary in anyone’s diet. Unlike some other controversial foods, there is absolutely no reason to consume this one. So don’t. This is a rare case where the risk-benefit analysis contains absolutely nothing in the benefits column. That means any risk, even a theoretical one, justifies avoiding this substance.

It may sound like I’m endorsing the “HFCS is bad” position, and certainly I have domestic reasons to go along with that, but I’m not. I honestly don’t care whether HFCS is bad for me. All I need to know about it is that it’s a diagnostic marker for junk food: if the product contains HFCS, it contains empty calories, was manufactured as cheaply as possible, and almost certainly tastes fake. Some of the same criticisms apply to sugar, but not all. Sugar is an ancient and sometimes necessary preservative, it’s never used as a low-cost option where HFCS would do, and it’s quite hard to run a kitchen without it. I can only cut back on sugar, but I can avoid HFCS entirely.

The dietary impact of eliminating HFCS is all good, even if we ignore the recent studies. Sodas and other sweets made with sugar are uniformly more expensive than similar products made with HFCS, so there’s an instant incentive to cut back on them. Highly processed entrees may contain it, but a meal made from scratch (which often cooks up just as fast as a TV dinner and tastes vastly better) doesn’t. Whether or not HFCS bypasses my satiety circuits, I’ll probably put fewer calories on my plate when I’m avoiding it, and the calories I do consume will automatically skew a bit more toward the nutrient-rich foods every dietitian advocates.

“But what about the poor?” comes the cry in every food discussion. Well, what about them? In the developed world, the days of the starving poor are long gone. Now, poverty correlates quite strongly with obesity. If avoiding HFCS prompts poor people to consume fewer but more nutrient-rich calories, that’s a big step in the right direction. The picture is more complicated in developing countries, many of which are struggling with simultaneous epidemics of obesity and starvation, but even there it’s unlikely that the empty calories of HFCS are helpful. People need food, not Coca-Cola.

To be clear, I’m not advocating any kind of legal ban on HFCS. Legislation and regulation should always rest on sound evidence, and we don’t have that here. However, if more people avoid this sweetener by choice – and both industry data and package labeling suggest that’s the trend – a much more powerful force will decide the issue: the law of supply and demand.