America has serious weight problems. That is a given. But why??
An interesting study by the Princeton Neuroscience Institute demonstrated that, in rats fed equal amounts of calories in sugar water and in water with high-fructose corn syrup, the rats fed high-fructose corn syrup gained significantly more weight than rats fed with sugar, even though their caloric intake was exactly the same. In a parallel study, rats fed high-fructose corn syrup over a period of six months gained 48% more weight than rats on a normal diet, and showed classic symptoms of obesity.
Research Associate Nicole Avena, now of the University of Florida, remarked that "the excessive consumption of high-fructose corn syrup found in many beverages may be an important factor in the obesity epidemic [in humans]."
Yet studies in humans indicate that high-fructose corn syrup does not trigger different responses than normal table sugar. So is high-fructose corn syrup to blame for our country's weight issues?
I decided to crunch some data and see how the consumption of high-fructose corn syrup by Americans (available from the USDA, Table 52) and historical rates of obesity in the American population (from the CDC, Table 2) have changed. The results are probably not surprising:
Figure 1. Historical rates of adult obesity (BMI>30, %, blue) and extreme obesity (BMI>40, %, red) in 20-74 year olds in the United States, vs. per capita high-fructose corn syrup consumption (lb/year, green).
That's right, we Americans eat over 40 pounds of high-fructose corn syrup per year!!!
Then I wanted to see if there were any statistical relationships here (Remember, correlation does not imply causation):
Figure 2. Relationship between adult obesity (%) and per capita high-fructose corn syrup consumption (lb/year) from 1974 to 2006.
Interesting that a linear relationship between the obesity of the American population and corn-syrup consumption explains over 80% of the variance in the two factors. The relationship suggests that, between 1974 and 2006, a yearly increase in high-fructose corn syrup consumption of 1.8 pounds corresponded with a 1% increase in the obesity rate of the American adult population. If this relationship is projected forward, an increase in our current high-fructose corn syrup consumption by 4.5% will correspond to over 3 million more Americans becoming obese!!
Of course, as I said before correlation does not imply causation, so we cannot be certain that high-fructose corn syrup alone is driving American obesity levels (it likely is a plethora of factors). And this is by no means a complete dataset. Indeed, it appears from the last few years of data that high-fructose corn syrup consumption has leveled off, yet obesity rates continue to rise.
So what do we do about this public health problem? Perhaps reducing the egregious import tax on sugar and reducing subsidies for corn would aid in this sweetener transformation. In the meantime, I have actively tried to limit high-fructose corn syrup from my diet for the past several years, and I must admit I feel a heck of a lot better because of it.