This is interesting and I always love urban planning discussions, but I feel there is something a little off about this. It seems to be suggesting that that reason people in non-urban areas are overweight / drive is because of dendritic street patterns, but those exist and are emblematic of a lower population density.

If you took my grandfather's fully rural town in the middle of Nebraska, there isn't much in the way of cul-de-sacs but people still drive everywhere because of - what seems to me - the more dominant issue of population density.