I hardly ever drank fizzy prior to dukan but i did drink squashes. Once I started this I bought Coke zero from Aldi, I keep it in the fridge so its lovely and cold and i average about three glasses a day. with my two glasses of water and 2/3 cups of hot drinks I get my fluids. I have on occasion had more than 3 drinks. I think its similar to a tolerated thing where if you stall with drinking too much coke then you know to back off a bit.