High or low adjustment to diet (4)
I believe the answer is:
tide
'high or low' is the definition.
I can't tell whether this defines the answer.
'adjustment to diet' is the wordplay.
'adjustment to' indicates an anagram.
'diet' is an anagram of 'TIDE'.
Can you help me to learn more?
(Other definitions for tide that I've seen before include "(With time) it waits for no man" , "Time and it wait for no man" , "Periodic water movement" , "Sea's ebb and flow" , "Powerful surge" .)