In an interview in the Science section of today’s NY Times, Carson Chow claims to have solved the obesity puzzle: Why is the obesity rate increasing in the U.S.? Chow’s mathematical analysis found that since the 1970s food production in the U.S. has increased considerably and that we consume most of that increased production. While he gestures to changes in consumption patterns, such as eating out and fast food, Chow’s concludes that we consume too many calories:
…it’s something very simple, very obvious, something that few want to hear: The epidemic was caused by the overproduction of food in the United States.
Well, what do people do when there is extra food around? They eat it! This, of course, is a tremendously controversial idea. However, the model shows that increase in food more than explains the increase in weight.
From the interview, I don’t see what the mathematician’s expertise contributed beyond some abstract social authority accorded to mathematicians. Chow’s conclusions is, as he says, obvious. Along with being obvious, his conclusion merely echoes the decade-old findings of USDA. The Agricultural Fact Book 2001-2002 covers food production increases and consumption patterns. In the U.S. daily per capita consumption has risen more than 530 calories since the 1970s. Further, the same report details how the foods we consume have changed: record levels of caloric sweeteners, record levels of calories from restaurants, record levels of refined grains (see Is Grandma to Blame for Obesity Today for more details).
More disturbingly, Chow ignores the social factors that complicate this picture. Obesity rates are not consistent across socio-economic and ethnic groups. Despite Chow’s claim to the contrary, various research details declining physical activity rates for children and adults. Some of that decline is related to our increasingly sedentary careers. Rates of decline seem correlated to demographic factors.
While the proximate cause for rates of obesity is increased calorie consumption, the ultimate causes are more difficult to determine. Chow alludes to some of the complicated social, cultural, and political causes for our increasing calorie consumption but doesn’t pursue them. A real solution to the obesity puzzle will have to identify and address the complex roots of our increasing weight gain.
For a different critique of Chow’s conclusion, see The Mathematician’s Obesity Fallacy in Scientific American.
[Reposted at PACHS.]