Junk : anything canned, processed to crap, has added preservatives, fillers, or "fake" foods (think cheese slices or CheeseWhiz)
I don't serve ANY junk here. The junkiest thing we eat are pretzels when we have a party for something. Once in a very GREAT while (like, twice a year) I will take them to Tim Horton's.
I really believe that nutrition is paramount to growth and development as well as behaviour. Besides, I wouldn't want to eat most of those so-called "kid-friendly" foods so I am not gonna offload that crap onto children.