"to go" means here as "to takeaway/ to takeout"(or "take home" if you are on the way home). Some people use "to go" as the same meaning of "left" Example: 1: There are still two days to go. (This situation is that you are expecting to have an event in two days time) 2: There's a long way to go. (It means that there's a long way to get to the result/destination) Best of luck! ;-)

It's American English for "to take away".