Surgically remove fat, essentially bit of belly to fill out behind (6)
I believe the answer is:
ablate
'surgically remove' is the definition.
(I've seen this before)
'fat essentially bit of belly to fill out behind' is the wordplay.
'essentially' indicates the central letters.
'bit of' says to take the initial letters.
'to fill out behind' becomes 'late' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The middle of 'fat' is 'a'.
The first letter of 'belly' is 'b'.
'a'+'b'+'late'='ABLATE'
Can you help me to learn more?
(Other definitions for ablate that I've seen before include "Aircraft able to land on ice" , "Surgically remove organs" , "do surgical removal" , "Surgically remove an organ" , "Remove an organ or bodily structure by surgery" .)