empty calories - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Food that has little or no nutritional value. For example, Snacking on beer and potato chips makes for a lot of empty calories. [1960s]