Had food (3)
'had food' is the definition.
(to eat is to have some food)
This is the entire clue.
(Other definitions for ate that I've seen before include "Worried" , "Tea (anag.)" , "included in one's diet" , "Consumed food" , "Greek goddess of mischief" .)
(Other definitions for eaten that I've seen before include "Crammed" , "This bread is soon forgotten, it's said" , "dined" , "Taken into the body as food" , "Scoffed" .)