A system comprising a riser reactor comprising a gas oil feedstock and a first catalyst under catalytic cracking conditions to yield a riser reactor product comprising a cracked gas oil product and a first used catalyst; a intermediate reactor comprising at least a portion of the cracked gas oil product and a second catalyst under high severity conditions to yield a cracked intermediate reactor product and a second used catalyst; wherein the intermediate reactor feedstock comprises at least one of a fatty acid and a fatty acid ester.