Result of eating for one, about to secure end of feast (7)
I believe the answer is:
satiety
'result of eating' is the definition.
(state of being sated or satisfied)
'for one about to secure end of feast' is the wordplay.
'for one' becomes 'say' (both can mean 'for example').
'about' is an insertion indicator.
'to secure' becomes 'tie' (tying is a kind of securing).
'end of' indicates one should take the final letters.
The final letter of 'feast' is 't'.
'tie'+'t'='tiet'
'say' going around 'tiet' is 'SATIETY'.
(Other definitions for satiety that I've seen before include "Full state" , "Having enough" , "Surfeit" , "stuffed" , "Boredom" .)