I think the hardest part about teaching kids the method that Andrea suggested is modeling it for them. I don't know that DH and I are capable of being good role models in that method, but we are at least capable of modeling the Sesame-street style "cookies are a sometimes food" behavior, and the girls have gotten that message already (I do hear "we don't eat ice cream all the time, only sometimes for a special treat" from them). I've also had occasions where they have turned down "treat" food because they weren't hungry, and when they get treat food, I emphasize to them that they don't need to eat the whole thing and should stop when they're full so they don't get a tummy ache.
I think we've done a better job of teaching them the value of exercise. They frequently do exercise play, and the other day spent like an hour pretending they were going to yoga class!
I don't remember what exactly the situation was with my dad when I posted last week. We're still in a holding pattern waiting for weekly blood test results to indicate whether he's got more time or less.