If it’s true that cities impose inherently healthier behavior on you, Turner reasoned, then people who move from cities to suburbs should get fatter—and vice versa. He began hoovering up data on 6,000 young Americans in their twenties to forties, tracking where they lived over a six-year period. He used satellite imagery and tallies of shops and churches to determine the level of sprawl in each subject’s neighborhood, then gathered information on each one’s weight.
When he examined the data, he discovered something surprising: People who moved between dense and sprawling neighborhoods didn’t change weight. Despite the claims of the new urbanists, Turner saw no evidence that one’s built environment has an impact on one’s health. “This idea that the built environment affects how much you weigh,” he told me, “is just wrong.”
But then why do cities harbor slimmer people who live longer and healthier than those in sprawl? Because, Turner argues, the populations are self-selecting. Highly active people who don’t like to drive—and who crave to make boatloads of money—naturally gravitate to places like New York, because that suits their chosen lifestyle. If we walk a lot here, it’s because we’re drawn to cities that force us to do so. The converse is also true: People who are heavier and less fit gravitate to suburbs precisely because that’s where they won’t need to walk—where nothing is possible without getting in a car. (Mind you, Turner’s rival scientists are not convinced by his argument. As one pointed out to me, moving to a differently dense area might take years to change your weight—longer than Turner’s time frame.) In Turner’s view, the logic of the urban health advantage is not only wrong, it’s backward. It’s not that New York makes us healthier. We make it healthier, by flocking here to live.
Ultimately, I’ve come to believe that Turner is likely correct—but so are the proponents of the urban health advantage. The two theories are not mutually exclusive. A city can be good for your health and, at the same time, attract healthy people.
The life-span miracle in New York—the X factor I’ve been searching for—is not one single cause, but a feedback loop. There’s no doubt that when New York cleaned up its crime in the nineties, it coasted to health as well as wealth in the high-tech boom: Wealthier people always live longer. But prosperity also wrought a cultural shift. New York once again became the city for young, ambitious strivers—precisely the sort that demand the cutting edge of healthy-living perks: an organic-food store on every corner, a yoga studio down the block, unreasonable amounts of sushi, clean parks in which to jog.
In a sense, the life-expectancy revolution challenges one of New Yorkers’ longest-held and oddly cherished self-mythologies: that our kinetic, aggressive city is a grim physical challenge, and we’re the Darwinian winners of the American race merely for surviving the mean streets. The truth is that the dystopic, self-destructive seventies are as gone as the days of the Bowery Boys.
Health has become our new urban stereotype. If New York City were still a raw, ungovernable failure, Frieden’s invasive nanny-state laws like banning smoking in bars or trans-fats would have made him a laughingstock. But the new New York has come to expect such measures; we probably even take a masochistic joy in being forced to behave ourselves. Hey, we’d been looking for an excuse to quit smoking anyway! And trans-fats—well, everyone knows that stuff’ll kill you, right? This is why Frieden will likely have no problem slapping another 50 cents onto the taxes for a pack of cigarettes this fall, either.
The urban health advantage is here, all right. And it is us.