Can't say at all, sorry. I have always drunk a lot of water, even before starting SW. So I guess it is the eating plan, not the drinking water that really does it, otherwise all the water I drank before SW would have meant I didn't need SW in the first place! I do think however that SallyVater is correct in that thirst can sometimes be mistaken for hunger which we try to fix with food instead of liquid, and you can prevent that mistake by not becoming dehydrated.