Warm hospital with encouragement to enjoy food (4,2)
I believe the answer is:
heat up
'warm' is the definition.
'hospital with encouragement to enjoy food' is the wordplay.
'hospital' becomes 'h'.
'with' means one lot of letters go next to another.
'encouragement to enjoy food' becomes 'eatup' ('eat up' is said to tell someone to eat their food).
'h'+'eatup'='HEAT UP'
(Other definitions for heat up that I've seen before include "Warm through" , "Make more intense" .)