Unless you are cooking in an environment where nutrution and dietary concerns are all important, ie. hospitals, nursing homes, jails, etc., I don't think you can come up with a solid rule to the question you are asking. The variables are too great: is it an app, an entree, a salad? What kind of cuisine - many cuisines favor vegetables and starches over meats, unlike many western countries that prefer a meat heavy dish. Even what kind of meat you are serving can and will make a difference. There are just too many things that go into it to come up with some hard and fast rule.