Crumbs eaten by binge eater (3)
I believe the answer is:
gee
'crumbs' is the definition.
(I've seen this before)
'eaten by binge eater' is the wordplay.
'eaten by' says the answer is hidden in the clue.
'GEE' can be found hidden inside 'binge eater'.
(Other definitions for gee that I've seen before include "Well I never" , "Wow!" , "Mild exclamation" , "Golly" , "that's something" .)