Beer belly of a being consumed by drink (6)
I believe the answer is:
paunch
'beer belly' is the definition.
(I've seen this before)
'a being consumed by drink' is the wordplay.
'being consumed by' means one lot of letters goes inside another.
'drink' becomes 'punch' (punch is a kind of drink).
'a' placed into 'punch' is 'PAUNCH'.
'of' is the link.
(Other definitions for paunch that I've seen before include "Protruding belly" , "corporation" , "Spare tyre" , "Large stomach or belly" , "Beer belly" .)