Ready with it, prepared type of fibre (7)
I believe the answer is:
dietary
'type of fibre' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'ready with it prepared' is the wordplay.
'with' is a charade indicator (letters next to each other).
'prepared' indicates an anagram.
'ready' put after 'it' is 'itready'.
'itready' is an anagram of 'DIETARY'.
Can you help me to learn more?
(Other definitions for dietary that I've seen before include "Related to fare" , "Relating to (healthy) eating" , "referring to everything taken down" , "relating to planned food intake" , "Relating to a food regime" .)