Consumed gram before barrier (4)
I believe the answer is:
gate
'barrier' is the definition.
(I know that gate is a type of movable barrier)
'consumed gram before' is the wordplay.
'consumed' becomes 'ate' (to eat is to consume food).
'gram' becomes 'g' (synonyms).
'before' is a charade indicator (letters next to each other).
'ate' put after 'g' is 'GATE'.
(Other definitions for gate that I've seen before include "Movable opening" , "Field entrance" , "Portal" , "Box office take" , "Five-bar opening?" .)