empty calorie

noun
1.
a calorie whose source has little or no nutritional value:
Junk food has only empty calories.
Origin
1965-70, Americanism
Contemporary definitions for empty calories
plural noun

calories obtained from food having no nutrients

Idioms and Phrases with empty calories

empty calories

Food that has little or no nutritional value. For example, Snacking on beer and potato chips makes for a lot of empty calories. [ 1960s ]