Food is consumed by harlequin, oafishly (6)
I believe the answer is:
quinoa
'food' is the definition.
(I have seen 'Vegan food' mean 'quinoa' so perhaps 'food' could also mean 'quinoa')
'consumed by harlequin oafishly' is the wordplay.
'consumed by' indicates the answer is hidden within the clue (inserted letters get consumed).
'QUINOA' is hidden in the letters of 'harlequin oafishly'.
'is' acts as a link.
(Other definitions for quinoa that I've seen before include "Grain-like crop from South America" , "Vegan food" , "South American grain" .)