The Netherlands is, hands down, the world's tallest country. Boasting a mean male height around 6 feet and one-half inch and an average female height of 5'7", the Netherlands makes the United States — which averages about 5'10" for men and 5'4" for women — seem positively tiny. Several scholars believe that the Dutch are so much taller than people almost everywhere else on earth because of economic inequality.
Height, like other human traits like intelligence, is a product of both genetics and one's environment. A man might be genetically equipped to grow to 5'10", but if he doesn't get enough nutrition as a kid, he might end up being significantly shorter. The correlation between nutrition and average height is so strong, in fact, that development economists often use height as a proxy for overall social well-being. Wealthy countries, where people may be more likely to have better nutrition as kids, are on-average much taller than poorer ones.
Computer scientist Randal Olson made a chart that showed how dramatically this effect transformed the Netherlands. Around 1850, the Dutch were some of the shortest people in Europe. But as Dutch GDP per capita increased, so too did their heights:
By the mid-70s, Olson finds, the Dutch started to pass the rest of the developed world in average heights. But it's the American figures that are really striking. The United States, for years on average the tallest country in the world, has since become one of the shortest among developed Western countries. That's because as heights have grown steadily across Europe, the United States hasn't gotten significantly taller, on average, since the 1960s.
Why? Olson points to a 2004 New Yorker article by Burkhard Bilger reviewing the research on height and wealth around the world. The academics Bilger spoke to suggested, very strongly, that economic inequality was likely a key cause of America's height stagnation. European countries have done a much better job ensuring equal access to nutritionally adequate food for all their citizens. Poor Americans, meanwhile, have made do with McDonald's:
As America's rich and poor drift further apart, its growth curve may be headed in the opposite direction, Komlos and others say. The eight million Americans without a job, the forty million without health insurance, the thirty-five million who live below the poverty line are surely having trouble measuring up. And they're not alone. As more and more Americans turn to a fast-food diet, its effects may be creeping up the social ladder, so that even the wealthy are growing wider rather than taller. "I've seen a similar thing in Guatemala," Bogin says. "The rich kids are taken care of by poor maids, so they catch the same diseases. When they go out on the street, they eat the same street food. They may get antibiotics, but they're still going to get exposed."
Steckel has found that Americans lose the most height to Northern Europeans in infancy and adolescence, which implicates pre- and post-natal care and teen-age eating habits. "If these snack foods are crowding out fruits and vegetables, then we may not be getting the micronutrients we need," he says. In a recent British study, one group of schoolchildren was given hamburgers, French fries, and other familiar lunch foods; the other was fed nineteen-forties-style wartime rations such as boiled cabbage and corned beef. Within eight weeks, the children on the rations were both taller and slimmer than the ones on a regular diet.
This theory isn't yet proven. For one thing, the researchers in the New Yorker article haven't yet found evidence that wealthier Americans are getting taller while less advantaged groups stagnate or get shorter.
It's also important not to forget other factors' roles, including genetics. Both Japan and Denmark are more economically egalitarian than the Netherlands, as measured by Gini coefficients. Yet neither country's people are taller, on average, than the Dutch.
So a lot of the questions about height around the world haven't been settled. But the theory that inequality is playing a huge role in making some people taller and others shorter is plausible — and somewhat disturbing.