Devouring rubbish including last scrap of meal, journalist ate too much (12)
I believe the answer is:
overindulged
'ate too much' is the definition.
'overindulged' can be an answer for 'ate' (overindulging is a kind of eating). I am unsure of the 'too much' bit.
'devouring rubbish including last scrap of meal journalist' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is present in the answer.
'journalist' could be 'ed' (short for editor) and 'ed' is found in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for overindulged that I've seen is " Spoilt".)