Nutritious and well done (4,3,3)

I believe the answer is:

good for you

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'well done' is the definition.
(I've seen this before)

I don't understand the rest of the clue.

(Other definitions for good for you that I've seen before include "wholesome" , "congratulations" , "Vegetables are meant to be" , "Well done! Health-giving" , "Very fatty steak may not be" .)

I've seen this clue in The Everyman puzzle in The Observer.

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