Source of lipids found in quickly-fried toast (6)
I believe the answer is:
salute
'toast' is the definition.
('salute' can be a synonym of 'toast')
'source of lipids found in quickly-fried' is the wordplay.
'source of' indicates taking the first letters.
'found in' is an insertion indicator.
'quickly fried' becomes 'saute' (I've seen this before).
The initial letter of 'lipids' is 'l'.
'l' put into 'saute' is 'SALUTE'.
(Other definitions for salute that I've seen before include "Bring hand smartly to cap" , "Ceremonial firing of guns" , "Greet in military fashion" , "Gunfire, perhaps" , "Hail with a gesture" .)