Ate in the café downstairs (3)
I believe the answer is:
fed
'ate' is the definition.
('feed' can be a synonym of 'eat')
'in the cafe downstairs' is the wordplay.
'in' indicates the answer is hidden within the clue.
'FED' is hidden within 'cafe downstairs'.
(Other definitions for fed that I've seen before include "Gave food to (someone)" , "Provided courses" , "supplied with power?" , "Banking authority" , "Given sustenance" .)