This is day 4 of my water (only) fast i'm still feeling slight hunger pangs i fasted one other time for 17 days straight (and numerous other times from 1-5 days each) and felt amazing once i got through the first few days i felt like i was walking on air one of the cool things about water fasting is that you lose weight quickly. Weight loss after 40 day water fast. In fact, research shows that you may lose up to 2 pounds (09 kg) each day of a 24- to 72-hour water fast unfortunately, a lot of the weight you lose may come from water, carbs, and even muscle.
weight loss after 40 day water fast