Dog set about some heavy food (6)
I believe the answer is:
stodge
'some heavy food' is the definition.
(I've seen this before)
'dog set about' is the wordplay.
'about' is an anagram indicator.
'dog'+'set'='dogset'
'dogset' anagrammed gives 'STODGE'.
(Other definitions for stodge that I've seen before include "treacle pudding?" , "Dull work" , "heavy fare" , "Heavy filling food" , "Heavy, often starchy, food" .)