Supervise the intake (4)
I believe the answer is:
diet
'intake' is the definition.
(I have seen 'regular intake' mean 'diet' so perhaps 'intake' could also mean 'diet')
'supervise the' is the wordplay.
'supervise' becomes 'die' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'die'+'t'='DIET'
Can you help me to learn more?
(Other definitions for diet that I've seen before include "Restrict food-intake" , "food one eats on a regular basis" , "Food - parliament" , "Food plan" , "Prescribed selection of foods" .)