This spawned the movement/book/blog The 100-Mile Diet. I love the idea of it, though I doubt I'll be able to put it into any kind of practice for a while. We try to buy from farmers' markets when we can, and given a choice between "northwest-grown" and elsewhere-grown at the grocery I'll choose the NW version, but other than that I cringe a bit to think that everything I eat has probably traveled farther than I have in the last year.
Anyway. One thing they've been commenting on is that a local diet - i.e., eating things only when they're in season - promotes a style of eating where you eat a few things nonstop for a few weeks, then change to a few new things nonstop, and so on. And I realized - my natural eating patterns follow this style exactly. I will want one or two things all the time for a week or two, and then suddenly get sick of them and search around for something new. This wreaks havoc with a normal modern diet, where we try to have the same staples on hand year round (which also makes shopping far simpler). But looked at from the evolutionary perspective of eating things as they are in season, it makes complete sense.