Tasty additive eaten by healthy men (5)
I believe the answer is:
thyme
'tasty additive' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'eaten by healthy men' is the wordplay.
'eaten by' says the answer is hidden in the clue.
'THYME' is hidden in the letters of 'healthy men'.
Can you help me to learn more?
(Other definitions for thyme that I've seen before include "Culinary herb of the mint family" , "Common herb" , "Flavouring" , "Shrubby herb" , "Sage's bedmate" .)