Gorge or diet: what's in it for northerner? (7)
I believe the answer is:
geordie
'for northerner?' is the definition.
(term for a person from Tyneside in NE England)
'gorge or diet what's in it' is the wordplay.
'what's in it' indicates a hidden word (I've seen this in other clues).
'GEORDIE' can be found hidden inside 'gorge or diet'.
(Other definitions for geordie that I've seen before include "Northern chap" , "Person from Newcastle-upon-Tyne?" , "Inhabitant of Tyneside" , "Newcastle person" , "Newcastle-upon-Tyne native" .)