Food served up in coffee breaks (4)
I believe the answer is:
beef
'food' is the definition.
(beef is a kind of food)
'up in coffee breaks' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'in' says the answer is hidden in the clue.
'feeb' is hidden in the letters of 'coffee breaks'.
'feeb' in reverse letter order is 'BEEF'.
'served' acts as a link.
(Other definitions for beef that I've seen before include "Muscle; meat; grievance" , "Brawn; grumble" , "joint, perhaps" , "Grouse - meat" , "nickname of US State" .)