Jul 01 2009

High Fructose Corn Syrup – The Latest Nutritional Boogeyman

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Much of the public’s attention regarding the rising incidence of obesity and issues related to weight control in general has been focused on good foods vs bad foods. Most popular diets are based upon the premise that the kinds of foods one eats is a dominant factor in determining weight – low carb vs low fat, for example.

Meanwhile, there is a growing body of scientific evidence, approaching consensus, that by far the dominant factor in weight control is the amount of calories one consumes, not the form in which those calories come. The best science-based nutritional advice for weight control seems to be – exercise regularly and practice portion control. For other health concerns, like heart health and avoiding diabetes – eat a well-balanced diet and get more of your calories from plants than animals.

That’s it in a nutshell, but it is hard to sustain a multi-billion dollar weight loss and self-help industry with such simple advice.

Further, it is human nature to prefer quick fixes and easy answers to tough love. Weight control is not complex, but it turns out to be very difficult for most people. Will power is not enough for 95% of the population. We can hardly blame people for what appears to be almost universal human traits. As a public health issue, approaches to obesity are not going to be found in scare tactics and weight loss schemes. The culture needs to change.

Part of that cultural change, in my opinion, is getting away from the very notion that the problem is caused by “bad foods”. The latest target of this approach is high fructose corn syrup (HFCS).   As reported by Consumer Reports:

In 2004, researchers from the Louisiana State University and University of North Carolina published a paper that theorized that high-fructose corn syrup in beverages could play a role in the obesity epidemic. They looked at the correlation between the 1,000 percent increase in high-fructose corn syrup consumption between 1970 and 1990, and a correlating rise in obesity rates. Because of the way the body metabolizes fructose from beverages, the researchers argued, it may play a role in the obesity epidemic.

Of course, this was a classic example of confusing correlation with causation.  The rising rate of obesity correlates with an overall increase in calories, and there is no evidence to implicate any particular source of calories as being the culprit.

Simple chemistry helps put HFCS into some perspective. Table sugar is sucrose, which is a combination of fructose and glucose – two common simple sugars. Corn syrup is mainly glucose, but HFCS is manufactured to have about 50% fructose and 50% glucose – the same ratio as sucrose or table sugar.

There are metabolic differences between fructose and glucose. Often studies showing that pure fructose can alter sugar and fat metabolism are presented as evidence against HFCS, missing the point that the ratio of fructose to glucose in the American diet has not changed with the introduction of HFCS.

A recent review of the literature published in the Journal of Nutrition, regarding the association of HFCS and obesity, concluded:

The panel concluded that evidence from ecological studies linking HFCS consumption with rising BMI rates is unreliable. Unlike some prominent epidemiologists, the expert panel concluded that the evidence from epidemiologic studies and randomized controlled trials is inconclusive. They also noted that there were inadequate data available that distinguish between HFCS consumption and sucrose consumption with respect to weight gain. Further, they acknowledged that while the sweetener level and type have changed over time, the fructose:glucose ratio in the U.S. food supply has remained the same for 50 y. Finally, the panel concluded that HCFS did not contribute to weight gain any differently than other energy sources.

In other words – HCFS is not the boogeyman. It is a distraction from the real issue – an increase in overall caloric intake. There may also have been a rise in total sugar intake, but the types of sugars have not changed. A diet with a large proportion of simple sugars is not a good idea because such a diet is also likely to contain too many calories, and high sugar intake increases the risk of diabetes.

Now, of course, the corn lobby is hard at work promoting this information – that HFCS is not the bad guy. But don’t make the mistake of assuming that because some information is in line with the interests of a specific corporation or industry that means the information is false. Any such information is likely to have winners and losers, that doesn’t mean it’s a conspiracy of the winners. We could just as likely conclude that negative information about HFCS is a conspiracy of the sugar cane lobby.

This does mean that we have to look for corporate interests in the published scientific data, and demand full disclosure of any potential conflicts of interest. There doesn’t appear to be any in the literature I reviewed – it seems there is a broad based consensus, not just corporate shills. I’m sure this won’t stop some from accusing me of being part of the corn lobby.

The bottom line is that HFCS is sugar. It is high calorie and has no other nutritional value other than as fuel. It should be consumed, like all sugars, in moderation. People should be aware that HFCS = sugar, and not be confused by this on food labeling.

But we will not impact the rise in obesity by treating HFCS as the culprit, or by replacing it with other sugar-based sweeteners.  We need more evidence-based public health measures to fight obesity – making healthy choices easier, making portion control easier, and disclosing calories on menus so that people know how many calories they are consuming. We don’t need boogeyman scare tactics.

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