get educated on Water Fasting before even starting one. If you're doing it ONLY for weight-loss, for example, I would say it's a lost cause. I can say that because I've been there! Many times.
I'm not being negative, just truthful. Eating right must be your first goal.
Being healthy: spirit, mind, and body, must be your first goal...the weight loss will then be a "perk" to the healthier YOU!