The definition of what constitutes a food desert is deceptively narrow and has little to do with actual nutrition. No, you can't find organic free-range avocados in many of these areas but you can find canned green beans and frozen broccoli, which for nutritional purposes are equivalent and much cheaper. We should be more concerned with adequate nutrition than the form of that nutrition.

Calling a place a "food desert" because people choose cheaper vegetables with less spoilage risk is condescending and easy to say from a position of economic privilege. I know an urban 1%-er that still eats canned green beans -- she loves the taste, having eaten them as poor child (I detest them, though for the same reason).