Are sprawling suburbs leading to sprawling waistlines?  Well the so-called smart growth movement would have you believe so, claiming that America’s suburban life — with its cars, strip malls, and lack of walkable communities — is a cause of obesity.  But according to a Heritage Foundation article by Wendell Cox and Ronald Utt, there is little weight to this lean claim.  They note that in Chicago, city dwellers weigh a statistically insignificant average of only 15 ounces less than their suburbanite cousins, while in the walkable borough of the Bronx, New York, 24 percent of adults are obese, compared with 21 percent nationwide.  So here’s at least one kind of population growth that doesn’t seem to play favorites.