Meaning and origin of "eat your heart out" [closed]

I never understood what this phrase meant or where it came from.

I've heard it used in the movie Grease:

Danny: You're looking good, Riz.
Rizzo: Eat your heart out.
Danny: But sloppy seconds ain't my style.

And other such times when used with a celebrity:

"Marilyn Monroe, eat your heart out!"


From the online dictionary of OALD: 1. eat your heart out (informal) used to compare two things and say that one of them is better Look at him dance! Eat your heart out, Fred Astaire (= he dances even better than Fred Astaire). 2. eat your heart out (for somebody/something)(especially British English) to feel very unhappy, especially because you want somebody/something you cannot have I'm not going to mope at home, eating my heart out for some man.


Copied and pasted from Wiktionary, from the first page of Google searches for "eat your heart out":

Etymology
Disputed. Three schools of thought exist:

  • From "This will eat your heart out.", suggesting that the recipient of the taunt will have their heart, the core of their being, eaten out with desire, bitterness, or pain.
  • From the 16th century "to eat one's own heart" (to suffer in silence from anguish or grief), possibly from the Bible "to eat one's own flesh" (to be lazy) The phrase "to eat one's heart out" appears as a formulaic phrase in the Iliad, meaning to experience extreme grief. (For instance, Iliad.24.128, many other locations.)
  • When used as the taunt "Eat your heart out, [someone]!" a suggestion that the recipient of the taunt "eat up" as much as they like. (From the same construction as "dance your heart out," etc.) Literally, similar to "have all you can eat!" Figuratively more akin to "experience me besting you."

Verb
to eat one's heart out
(idiomatic) To feel overwhelming sorrow, jealousy or longing, to grieve.
The Germans are eating their hearts out over their defeat against Spain in European championship games for soccer.
Eat your heart out, pal! We won the title!