Urban sprawl is ugly, inefficient and bad for the environment. It’s also – quite literally – sickening. The unhealthiness of spread-out, car-dependant neighbourhoods is clearly spelled out in a new study by St. Michael’s Hospital researchers. Urban planners, municipal leaders and city residents would be wise to pay close attention.

Scientists from the hospital’s Centre for Research on Inner City Health found risk of obesity and diabetes was elevated by as much as 33 per cent in suburban areas of Toronto with poor “walkability.” Simply put, the layout of a neighbourhood has a big impact on the health of the people who live in it.

The findings were published this past week in the online journal PLOS One.

Older, downtown areas are more walking-friendly because they’re divided into shorter city blocks. There’s a higher population density, so residents aren’t as spread out. And there are more places to go (such as stores and services) within walking distance. In contrast, many outlying Toronto neighbourhoods don’t even have sidewalks.

Furthermore, in contrast to sedentary suburbanites, people in walkable communities don’t just stroll more often, they also cycle and use public transit more frequently and are significantly less likely to drive. All that translates into solid health benefits.

It’s important to note that other factors, beyond walkable neighbourhoods, do affect risk of obesity. Affluence and ethic origin play a big role too. And it’s possible that walking-friendly neighbourhoods don’t so much inspire residents to use their legs as attract people who were walkers in the first place.

None of that should deter city planners and urban activists from pushing to cut sprawl and create walkable communities. Canada is facing an obesity epidemic. And rather than throw up their hands and lament that there’s not much that can be done, policy-makers can play an active role by promoting neighbourhoods specifically designed as healthier places to live.

An emphasis on creating fewer single-family homes, and more multi-unit residential buildings, is fundamental. So are zoning initiatives aimed at developing more easy-to-walk-to mixed use areas, expanded public transit lines, and bicycle paths. Sidewalks would be nice, too.

Discouraging driving and broadening opportunities for strolling, cycling, and using public transit don’t constitute a “war against the car,” as Mayor Rob Ford calls it, but part of a battle for better health. Urban sprawl is the real foe. And a determined effort is required in order to defeat it.