Poe said to become fatty (7)
I believe the answer is:
adipose
'fatty' is the definition.
(synonyms)
'poe said to become' is the wordplay.
'to become' is an anagram indicator.
'poe'+'said'='poesaid'
'poesaid' with letters rearranged gives 'ADIPOSE'.
(Other definitions for adipose that I've seen before include "Like fatty tissue" , "Containing fat" , "Relating to fat" , "I soaped up with fatty kind of tissue" , "Relating to fatty tissue" .)