To clarify my earlier post, I would always at least gently offer to pay and if the person I am with wants to pay for their own meal, not an issue with me either, more of a cultural/traditional thing with me than expecting anything specific in return.

I agree with Lynn that restuarants over do portions and can offer a lot of fattening items. I usually eat at home myself most of the time. It is nice once in a while to enjoy a good meal at a place where people can prepare food with far more training than I have as a cook. I attend Karate with a chef who is very much on the "farm to table model" (fresh local produce and meats, no canned or frozen ingrediants) and I enjoy having lunch at his place every now and again.