Food? Say grace initially (3)
I believe the answer is:
egg
'food?' is the definition.
(egg is a kind of food)
'say grace initially' is the wordplay.
'say' becomes 'eg'.
'initially' suggests taking the first letters.
The initial letter of 'grace' is 'g'.
'eg'+'g'='EGG'
(Other definitions for egg that I've seen before include "Cooked breakfast staple" , "Reproductive unit" , "Spur" , "Baby carrier?" , "Early stage of development" .)