I think I have the same problem, but in the opposite way. I live by myself and end up wasting too much food because I don't eat all that I buy, but find it difficult to buy less. For example, I threw out half a lime this morning. I bought it a few days ago only needing a few slices, then didn't use the rest.

In the case of a single lime it isn't really possible to buy less (and at least limes are cheap), but with other items I could benefit from more exact planning.