Exercise is able to provide nourishment (5)
I believe the answer is:
pecan
'nourishment' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'exercise is able to' is the wordplay.
'exercise' becomes 'pe' (Physical Education).
'is able to' becomes 'can' (if you can do something you are able to do it).
'pe'+'can'='PECAN'
'provide' acts as a link.
Can you help me to learn more?
(Other definitions for pecan that I've seen before include "US nut tree" , "Something like a walnut" , "Pinkish-brown nut used in American pie" , "Smooth pinkish-brown nut, nice in pie" , "Edible nut like a smooth walnut" .)