Fast Food restaurants make a point to market to young people, particularly children.  There are many reasons as to why they market to children. 

If a child wants something, and beggs long enough or throws a bad enough tantrum, then they are likely going to get what they want.  This means that if they are begging to go to McDonald's for some food, to get one of their toys, or to play in one of their playlands, then when it is decided that they can go, someone has to drive them there.  Children mean multiple customers, they will likely go there with parents, granparents, and friends.  Also, if you esablish something "good" in their mind when they are children, the image of that fun time or good food, will likely stick in their mind and they will return to that same business or even that paritcular place for the rest of their life. 

Fast Food resaurants also use symbols to get something embedded in a childs mind.  Examples of these symbols are Ronald McDonald, and Our Friend the Atom.

The fast food industry also markets using pathos, pulling at your heart strings.  By using pathos they try to show you that they care about you and their other customers.  If they make you think that they care, then you are more likely to go the fast food restaurants that you think care about you, than to the ones that you think only want you for the money you bring in.

The fast food industry markets to parents by making them think that if they take their children to the fast food restaurant that they want to go to then they are good parents.  They especially try to make them think that going to tehir favorite fast food restaurant will make them a better parent.