I was homeless for three years in Saint Louis (also lived in West/South Chicago for some time) and was the healthiest I ever had been in terms of weight. You don’t have to patronize these places, even in so-called food deserts.
Wasn't in a food desert though, i don't think those exist in my country.
I assume the grocer logic is something like "make them walk past and consider all the other stuff before they get to what they really want (junk food)"