I think it's worth noting too, that buying food packaged in large containers/cans isn't necessarily the best idea, unless you're prepared to repackage into smaller containers (bit of a hassle, and simply won't work with some products). And, of course, with some foodstuffs, once you've opened a [large] container, you're forced to consume the contents in short order, or refrigerate, the chances of which would be slim in a disaster.

As has been mentioned, look to backpacking-related resources for worthwhile food-related guidance. After all, backpacking is a form of "bugging out," just with everything on your back.