They are usually high in sugars and fats, which are at the top of the food pyramid as being bad for you and used only in moderation. Also, why do you think they're called JUNK foods?
Junk food is things that have sugar or caffeine in it. Ex. candy is a bad habit of children. Children these days are overweight. One child is over 400 lbs. That's are not good. !!! how bad are they...