* They were very poor: This is evident from the fact that they live in a tiny, rundown house and Charlie only gets one small chocolate bar a year for his birthday.
* Their diet was likely meager: Charlie's mother mentions how she'll save the chocolate bar for Charlie to eat after dinner, implying that their meals were probably quite plain.
* They did eat cabbage: Charlie's mother is mentioned as having a cabbage soup recipe that Charlie didn't like very much.
While it's not explicitly stated what the family typically ate, it's safe to assume their meals were simple and probably not very exciting, given their financial constraints.