In restaurants we demand some veg (5)
'some veg' is the definition.
(I've seen this before)
'in restaurants we demand' is the wordplay.
'in' indicates a hidden word.
'SWEDE' is hidden in the letters of 'restaurants we demand'.
(Other definitions for swede that I've seen before include "North European", "Someone from Gothenburg", "Nobel for one", "N European", "Native of Stockholm".)