I am the same as toomuch - I drink both coke zero and dr. pepper zero and only have a can. I try not to have it EVERY day but it has never affected my weight losses.
I'd avoid diet coke its coke zero you should drink instead its because all the other coke have citric acid in which can bring you out of ketosis I have coke zero de pepper zero and there are some other drinks which don't have Citric acid