I think there is something to this study, but not in the way they’d like it to play: our cities are filling with “replacement Americans” (generally from Latin America and Asia) who are much “lighter” than the multigenerational welfare sows they are displacing in those cities (that have had their “cash-for-kids” program cut ff since the 1996 welfare reform - thus dramatically reducing their numbers).
Anyone who has actually been to the welfare reservations in the cities know there is no way even the heaviest “Wal-Mart types” can hold a candle to some of their urban counterparts raised on gubmint cheese and KFC.
Possibly....I recall a sports story from the 1980’s though commenting on “Midwest (Brawn?) and Coastal Quickness.” Basically the linemen were farm boys and then the skill positions were urban kids.
I realize that’s not a valid cross-section though....