They announce food to be eaten by supporters (8)
I believe the answer is:
fanfares
'they announce' is the definition.
The definition suggests an adverb but the answer is not.
'food to be eaten by supporters' is the wordplay.
'food' becomes 'fare' (fare is a kind of food).
'to be eaten by' is an insertion indicator (inserted letters get eaten).
'supporters' becomes 'fans' (fan is a kind of supporter).
'fare' going within 'fans' is 'FANFARES'.
Can you help me to learn more?
(Other definitions for fanfares that I've seen before include "Ceremonious soundings of trumpets" , "ceremonial blasts of trumpets" , "Flourishes of trumpets" .)