Exercise is able to provide some nourishment (5)
I believe the answer is:
pecan
'some nourishment' is the definition.
The definition and answer can be both things that one consumes for nourishment as well as being singular nouns.
Maybe you can see an association 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 "Smooth pinkish-brown nut, nice in pie" , "Species of hickory - edible nut" , "US nut tree" , "Type of nut" , "Nut with sweet oily kernel" .)