Read more of Daniel Engber's columns on obesity and health care reform.
Related to the health-wealth gradient is what we might call the "girth-wealth" gradient. In 1989, a pair of researchers named Albert Stunkard and Jeffery Sobal pored over several decades' worth of data on obesity rates and concluded that socioeconomic status and body size were inversely related among women in developed countries. A recent review by Lindsay McLaren found that the pattern of poor women being fatter than rich ones has begun to spread into the developing world. (For men, the girth-wealth gradient tends to go in the opposite direction, and the health effects of obesity are somewhat diminished.)
Both gradients appear to be deeply entrenched in modern life, and we shouldn't count on universal health coverage to erase either one. International surveys suggest that the development of free medical care—through the National Health Service in the United Kingdom, for example—doesn't much alter the fundamental relationship between health and wealth. It's also not clear that expanded health coverage is likely to make the poor any less fat. A study published over the summer even suggests that the opposite might be true—a public option could end up increasing obesity rates among the newly insured.
The mere existence of these gradients does suggest that if we spread around the wealth a little better, poor people would end up healthier—and thinner—than they were before. According to British economists Richard Wilkinson and Kate Pickett, this benefit wouldn't necessarily come at the expense of the rich. Their new book, The Spirit Level: Why Greater Equality Makes Societies Stronger, uses data from the World Bank, the World Health Organization, and the U.S. Census to argue that disparities in income produce a wide range of social ills—like obesity, teen pregnancy, mental illness, murder, and infant mortality—that could be addressed by shrinking the gap between the haves and the have-nots. Indeed, the United Kingdom's Labor government has taken up this charge in recent years, with a series of measures to reduce inequality in the name of public health.
The United States could try to do the same, by raising the minimum wage or increasing earned-income tax credits. In 2001, Princeton economist Angus Deaton considered the implications of a Robin Hood health policy. (His thoughtful and accessible paper on the topic is well worth reading.) Deaton concluded that a direct redistribution of wealth might be an efficient way to improve the health of the poorest Americans. But he warned that equality shouldn't be treated as an end in itself. A fancy new treatment, for example, might steepen the health-wealth gradient when it's first introduced, since only the rich can afford it. But that doesn't mean we should avoid medical breakthroughs for the sake of public health. According to Deaton, a saner approach would be to invest in education, since better schooling seems to improve your health and raise your income, too.
You don't hear anyone suggesting that better schools could pay for health care reform, though. Instead, we've pegged our hopes on a national weight-loss regime—a redistribution of girth instead of wealth. If being poor can make you fat and vice versa, then we can't solve one health problem while ignoring the other. Yet we act as though the war on obesity can be separated out from the war on poverty: Consider the soda tax—an anti-obesity measure that shifts money away from the poor.
Why are we so fixated on body size? Another social gradient might be playing out in this policy debate: It turns out that the richer you are, the more likely you are to be on a diet. (Among fat people, more wealth correlates with lower self-esteem.) So it's only natural that we'd be hung up on the issue of obesity—we're projecting. In my next column, I'll look at how this tendency might itself be a risk to public health.