I have been thinking about the same for a long time. It is not just the rising food cost; you don't get your money's worth these days. The quality of the food that you pay so much for has deteriorated miserably. Moreover, it is loaded with pesticides or prepared in unhygienic conditions, and that places you at a risk for all sorts of medical disorders.
Eating out less is a great way to cut food costs. I follow that method myself. I hardly eat out nowadays. Another way is to prepare as much as possible at home. I also maintain a kitchen garden and try to grow my own vegetables and fruits. It is difficult at first, but once you get the hang of it, growing a kitchen garden is a highly fruitful, fulfilling, and exciting activity.
Cheers!