You really should see this great video from Food Myth Busters about the advertising of fast food and “junk” food to kids. It is an excellent look at the consequences of food marketing to children, including the many forms this marketing can take.
I think that the message that parents (among others, like school administrators) need to take responsibility for limiting children’s exposure to these marketing efforts and –more importantly — set a good example is important.
It’s only about 6 minutes long, so you will have plenty of time to check out the excellent information on the rest of the site.
In case you were expecting some thing from the other MythBusters, they have videos about food, too.