There's additional issues there though. If a family is living in low cost or temporary accomodation, they may not have the refridgeration/cooking facilities that most of us take for granted, and for parents working long hours lack the time for extensive food preparation. Putting a frozen meal in a microwave might be the best they can accomplish after working until late.
There's also issues of some areas not having easy access to low cost fresh foods, and of course some people lacking the education to know how to cook properly.