A bit of food left by solver who preferred a pint (6)
I believe the answer is:
morsel
'a bit of food' is the definition.
(morsel can mean a piece of food)
'left by solver who preferred a pint' is the wordplay.
'left' becomes 'L' (common abbreviation).
'by' means one lot of letters go next to another.
'solver who preferred a pint' becomes 'Morse' (fictional alcohol-loving detective Inspector Morse).
'l' after 'morse' is 'MORSEL'.
(Other definitions for morsel that I've seen before include "A scrap or shred of food" , "a little food" , "A shred as of bread" , "Small mouthful of food" , "A small amount of food, just a piece" .)