Fancy putting limit on staple food (7)
I believe the answer is:
caprice
'fancy' is the definition.
(thesaurus)
'limit on staple food' is the wordplay.
'limit' becomes 'cap' (capping is a kind of limiting).
'on' means one lot of letters go next to another.
'staple food' becomes 'rice' (I've seen this before**).
'cap'+'rice'='CAPRICE'
'putting' acts as a link.
(Other definitions for caprice that I've seen before include "Sudden mood change" , "Whimsy" , "Sudden impulse" , "Sudden change of mind" , "A whim, or piece of music in lively fanciful style" .)