Urge for food? (3)
I believe the answer is:
egg
This clue is a double definition.
'urge' is the first definition.
(as in egging someone on)
'food?' is the second definition.
(egg is a kind of food)
'for' is the link.
(Other definitions for egg that I've seen before include "Food from a hen" , "Incite; ovum" , "Source" , "Cooked breakfast staple" , "On the face, it's embarrassing" .)