Food rejected on empty stomach (4)
I believe the answer is:
nosh
'food' is the definition.
(nosh is a kind of food)
'rejected on empty stomach' is the wordplay.
'rejected' says the letters should be written in reverse.
'empty' means to remove the middle letters.
'stomach' with its centre taken out is 'sh'.
'on' backwards is 'no'.
'no'+'sh'='NOSH'
(Other definitions for nosh that I've seen before include "Food (coll)" , "eating this?" , "Food (sl.)" , "(Eat) a snack" , "'Food, grub (4)'" .)