To shed light on the issue, Stanford Center on Longevity faculty affiliate, Professor Larry Frank and his colleagues asked urban dwellers about their walking habits and vehicle usage. They found that people who valued being able to walk, and who lived where they could walk comfortably, drove fewer miles and were less likely to be obese than those who didn’t place high value on being able to walk, even if those folks less eager for a stroll lived in very walkable areas.

Location, it might be said, trumps motivation.

The study first looked at people drawn from two groups. Researchers asked those who had lived in their neighborhood for less than 3 years how much the “walkability” of the neighborhood, that is, the ease with which it enabled walking both for pleasure and doing important tasks like running errands, had figured in their choice of location.

The authors asked a second group –– those who had lived in their neighborhood for longer than 3 years –– a hypothetical question: If they were able to choose a neighborhood, how important would walkability be to that choice? They also asked this group to consider specific tradeoffs, such as urban vitality versus living in a quiet area with single homes, or living in a neighborhood that mostly accommodated automobiles versus pedestrians and cyclists.

The authors then analyzed the entire study population according to two parameters: the value they placed on a walkable neighborhood, and the character of the neighborhood they lived in at present. The most striking differences in travel habits and obesity were between persons who both preferred and lived in a walkable neighborhood, and those for whom walkability was a low priority and who lived in a vehicle-oriented neighborhood.

During a two-day travel analysis, 33.9 percent of those who preferred a walkable neighborhood –– and lived in one –– walked for pleasure or tasks; only 11.7 percent were obese. They drove only about 25.8 miles per day on average. In contrast, among those who placed low value on walkability and lived in a car-dependent environment, only 3.3 percent walked at all over 2 days, and they drove much more: 43 miles per day. Their obesity rate was nearly double that of the people who preferred and lived in walkable neighborhoods: 21.6 percent were significantly overweight.

The study thus suggests that environment in which we live can only help us to stay fit if we’re willing to use its walkable amenities –– and not just head for the car every time we need to pick up a quart of milk.

For the complete study, see:

Frank, Lawrence D., et al. (2007) Stepping towards causation: Do built environments or neighborhood and travel preferences explain physical activity, driving, and obesity? Social Science & Medicine, 65, 1898–1914.