Meaning: Food that is bad for us because it contains large amounts of harmful substances like artificial colouring, preservatives, salt, refined sugar, and so on.
- No wonder people in Western societies are so unhealthy, overweight and unattractive. Have you seen the sort of junk food they're addicted to?
- Food companies spend millions developing and advertising junk foods that make us fat, sick and ugly because the profits from this sort of food are far greater than the profits made by selling healthy foods.
Origin: Probably related to the fact that junk is something useless and of no value, and this is a good description of the foods that are called junk foods.