Our chap, surrounded by extremes of good food, is a glutton (8)
I believe the answer is:
gourmand
'a glutton' is the definition.
(synonyms)
'our chap surrounded by extremes of good' is the wordplay.
'chap' becomes 'man' (chap can mean a man).
'surrounded by' is an insertion indicator.
'extremes of' means to remove the middle letters.
'good' with its middle removed is 'gd'.
'our'+'man'='ourman'
'ourman' going within 'gd' is 'GOURMAND'.
'food is' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for gourmand that I've seen before include "Person devoted to eating and drinking" , "One who enjoys eating" , "Foodie" , "one putting loads away?" , "Food buff" .)