Interesting. My read on this map is that it also tracks the urban/non-urban breakdown very neatly: as you get out of the urban code, obesity %s increase dramatically.
i.e. there are 8 grocery stores within a few minutes walk, but they are all smaller - some just sell produce, others are smaller versions of suburban grocery stores.
I could see it being a 'rural' thing, but the ring is weird.
This is, by the way, a strong conflict with East Coast cities in the US, where there's a decided "obese area" visible. I don't have insight into those from the ground level.
That sort of access also makes those places more desirable, and thus more expensive, and thus more likely to be populated by rich people.