E.g. almond, almost entire, prepared as sustenance (8)
I believe the answer is:
nutrient
'sustenance' is the definition.
(sustenance can mean nutrition)
'e g almond almost entire prepared as' is the wordplay.
I cannot really understand how this works, but
'e' is present in the answer.
'as' could be 'in' (I've seen this in other clues) and 'in' is present in the remaining letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for nutrient that I've seen before include "It gives energy and builds tissue" , "Something providing nourishment" , "Good food" , "provider of sustenance?" , "Source of nourishment" .)