Live on a half diet of vegetables (4)
I believe the answer is:
beet
'of vegetables' is the definition.
The definition suggests a singular noun which matches the answer.
'live on a half diet' is the wordplay.
'live' becomes 'be' (synonyms).
'on' means one lot of letters go next to another.
'a half' indicates taking half.
'diet' cut in half is 'et'.
'be'+'et'='BEET'
Can you help me to learn more?
(Other definitions for beet that I've seen before include "The mangelwurzel, for instance" , "Sugar-yielding plant" , "An edible root plant" , "E.g. chard, mangelwurzel" , "Root used as a source of sugar" .)