Food is the code word for Crack Cocaine. There are many different code/street words for Crack. It is the most common one used in Edmonton, Alberta.
It lets dealers ask people on the side of the street if they want to buy some, without being too obvious to any cops or anyone that doesn't know they're using code.
Dealer: "You need some food?"
Random Person 1: "Nah, dude, I'm good. Got plenty of groceries at home."
Random Person 2: "He was talking about crack dude."
Random Person 1: "Damnit."