eat one's heart out, to

Feel bitter anguish, grief, worry, jealousy, or another strong negative emotion. For example, She is still eating her heart out over being fired, or Eat your heart out-my new car is being delivered today. This hyperbolic expression alludes to strong feelings gnawing at one's heart. [Late 1500s]

To worry excessively. “Eating our hearts for weariness and sorrow” appeared in Homer’s Odyssey (ca. 850 b.c.). Presumably here, as in later usage, eating one’s heart is analogous to consuming one’s inmost self with worry or anxiety. Later English writers, including John Lyly and Sir Francis Bacon, ascribed the saying to the Greek philosopher Pythagoras, who also used it (“Eat not thy heart,” Praecentum, ca. 525 b.c.). A modern slangy variant invoking a different feeling is the spoken imperative eat your heart out, meaning “doesn’t that make you jealous.” A translation from the Yiddish es dir oys s’harts, it originated in America in the 1960s and was popularized by the television show Laugh-In.