Had plenty of food - but about a quarter had no food! (7)
I believe the answer is:
feasted
'had plenty of food' is the definition.
The definition and answer can be both related to consumption as well as being past participle verbs.
Perhaps you can see a link between them that I can't see?
'about a quarter had no food' is the wordplay.
'about' is an insertion indicator.
'quarter' becomes 's'.
'had' means one lot of letters go next to another.
'no food' becomes 'feted' (I can't justify this - if you can you should give a lot more credence to this answer).
'a'+'s'='as'
'as' put within 'feted' is 'FEASTED'.
'but' acts as a link.
(Other definitions for feasted that I've seen before include "Banqueted" , "Ate high off the hog" , "Had a lot to eat" , "Ate lavishly" .)