Food deserts are a big problem. Most of the urban food deserts developed after major riots burned down existing grocery stores in the late 60s (and then again in the 80s in LA).
New food deserts now exist in Minneapolis (and likely other cities as well) after the recent rioting and burning there:
Ironically, in the most recent riots, many - perhaps most - of the destructive rioters were middle-class "activist" kids who don't have to live with the results of their actions.