Son cutting meals by reforming diet perhaps (8)
I believe the answer is:
assembly
'diet perhaps' is the definition.
(diet is a kind of assembly)
'son cutting meals by reforming' is the wordplay.
'son' becomes 's'.
'cutting' is an insertion indicator (some letters cut their way into a word).
'reforming' indicates anagramming the letters.
'meals'+'by'='mealsby'
'mealsby' is an anagram of 'asembly'.
's' inserted inside 'asembly' is 'ASSEMBLY'.
(Other definitions for assembly that I've seen before include "Body of people that meets" , "Bless May (anag.)" , "Group gathered together for a common purpose" , "Gathering of people for a common purpose" , "Group meeting" .)