How long does it take to get into ketosis and what happens when you do? Do you lose a lot of weight? How do you do it, by only drinking water??? I'm kind of new to this fasting thing, even though i've done it a few short times before (like 3 or 4 days fasts, my longest was 5 once). I hear that ketosis is the best thing for losing weight but how do you get into it?