|food that is low in nutritional value, often highly processed or ready-prepared, and eaten instead of or in addition to well-balanced meals|
junk food n.
Any of various prepackaged snack foods high in calories but low in nutritional value.
Prepackaged snack food that is high in calories but low in nutritional value; also, anything attractive but negligible in value. For example, Nell loves potato chips and other junk food, or When I'm sick in bed I often resort to TV soap operas and similar junk food. [c. 1970]