I'd say that on average, my food memory is about 2-3 days. I say this because I've gotten into the habit of eating breakfast at work, and I keep some breakfasty-type foods there for that purpose. I usually like to have at least two or three different kinds of things to eat so that I don't have to have the same thing two mornings in a row. For example, this morning I had a bowl of oatmeal. Yesterday, I had toaster pastries. Tomorrow, I'll probably have oatmeal again, since those are the only two things I have here right now, but then again, I might go to the store and buy something else because every once in a while I like to mix it up and have something different on the third day.