I don't know about US. But, here in Europe, this is so true to not being a notice. If you live in "Suburbia" you walk less, if you live nearer to the center you walk more. Who walks more is healthier... As an added bonus, in the center of european city there are no (or very few) cars... believe me or not, this also help to be healthier...
The notice, for me, is that that earns a NYT article and a front page in HN...
There may be more to the methodology than presented, but from what I read, it stinks. They merely looked at height, weight, and location without controlling for income.<p>Wealthier people are in better shape and weigh less (for the first time in history we live in a society in which poor people still earn enough money to become obese!).<p>More walkable areas may be more desirable, and may therefore have higher prices, and may therefore only be available to wealthier (and thinner) people.<p>The article doesn't establish causality <i>at all</i>.
Somewhat related: <a href="http://www.walkscore.com/rankings/" rel="nofollow">http://www.walkscore.com/rankings/</a><p>The data is sorta flawed- it ranks SF #1 since their methodology doesn't take into account steepness of terrain- but nevertheless, pretty interesting.