Most downtowns in the states do not have a grocery store anymore. If you only eat at restaurants (there are many fine ones around) you are fine, but forget about a home cooked meal unless you drive to the suburbs, at which point you may as well get a weeks worth of food just like everybody in the suburbs does.

Note that there are exceptions where there are stores. However before you point them out, remember that in a generalization there is specifics that are wrong. Even if there are stores, are there enough stores to cover each tiny neighborhood or do a lucky few get stores and the rest have to drive because the stores are not close enough to be useful.