It would be an interesting map, to see how many people lived substantially closer to a McDonald's than to a place that sold pasta for reasonable prices. I guess you might have to toss in Subway.

Here, the decent groceries are a bit over a mile away, two are a bit closer than the McDonald's, one is a bit further. 2 Subways beat them all.

I guess such a map would have uninteresting regions where it was more of a choice (rural residential lots).