From Longman Dictionary of Contemporary Englishjunk foodˈjunk food (also junk) noun [uncountable] informalDF food that is not healthy, for example because it contains a lot of fat, sugar etc → fast food
Examples from the Corpus
junk food• They have man-aged to combine the worst features of institutional food and junk food.• Chavez, at 33 and perhaps fighting for the last time, eats junk food, drinks beer and loves to party.• This is just my kind of diet - no junk food, plenty of fruit which I love.• Probably because of a diet of junk food and a general reluctance as a nation to exercise.• It's too easy to end up living off junk food.• Large-muscle coordination comes from riding bikes and climbing trees, not from watching junk food commercials where other kids play and run. 