That, besides the number of gyms and liposuction clinics, is why New Yorkers are skinny compared to the nation as a whole. "In very dense urban environments, you get local shops and facilities mixed up together," says Townshend. "People tend to use those more. There's an awful lot more walking involved, just because of the inconvenience of driving." High-density housing, in other words, can help create what is known in the trade as the "eco-slob" effect, whereby the healthy, environmentally friendly option is also the path of least resistance."
In the States,"Dr Reid Ewing of the University of Maryland published a paper on the relationship between suburban sprawl and health. His nationwide study offered the first direct evidence that adults in low-density, car-dependent housing weighed more, walked less and were more likely to be obese. Meanwhile, a study of 1,100 Atlanta residents carried out by Professor Lawrence Frank of the University of British Columbia reported a correlation between driving and weight gain. According to his findings, each additional hour spent in a car per day is associated with a 6% increase in the likelihood of obesity.
So could architects and planners halt the nation's obesity crisis? They can certainly help, but all the intelligent architecture in the world won't stop people from popping to the corner shop in their SUV to pick up a multipack of Hula Hoops. Which means we're back to the idea of the eco-slob: the healthy option has to be made the easiest option.