Cost of food while camping ... does it have to be high?

We do weekend camping trips in the summer with out Good Sam club members. We often joke that we're an eating club that enjoys camping. On these trips our food is brought from home, for the most part. But in the winter, living in the camper for several months, we eat pretty much as we do at home but a few more restaurant meals than at stick home, but that's because there we live an hour or more and many miles from restaurants.