Wife gets in health food possibly for strength (5)
I believe the answer is:
brawn
'for strength' is the definition.
(brawn is a kind of strength)
'wife gets in health food possibly' is the wordplay.
'wife' becomes 'w'.
'gets in' is an insertion indicator.
'health food possibly' becomes 'bran' (bran is healthy food).
'w' placed inside 'bran' is 'BRAWN'.
(Other definitions for brawn that I've seen before include "meatloaf" , "Strength; a jellied loaf" , "Muscular strength" , "Jellied meat - muscle" , "This is strong" .)