Why do some cartoons try to teach kids not to eat certain foods?

Well, Most kids like to watch cartoons as kind of an escape from reality (not really) but they don't want to hear the same things repeated in a show that their parents already tell them. As far as that particular cartoon, that's the entire point of it. Most 7 year old kids understand the difference between fiction and reality. I think they will go their own way on most things regardless of the show. If they like vegetables, then they will eat vegetables.