Heavy filling food (6)
I believe the answer is:
stodge
'heavy filling food' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for stodge that I've seen before include "Heavy and indigestible food" , "Sticky stuff" , "Heavy, often starchy, food" , "'Heavy, starchy food (6)'" , "Steamed pudding" .)