Start eating (4)
'start eating' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dig in that I've seen before include "Begin eating heartily" , "prepare trench" , "Start to scoff" , "Start eating (informal)" , "Begin eating (informal)" .)
(Other definitions for chew that I've seen before include "champ" , "Treat for dog" , "Ruminate" , "Work between teeth, masticate" , "Try to eat" .)