Day one was incredibly horrible. My first fast ever and im done with day 6 in a few hours. Feels great and since you fasted before you know it also! I haven't been half as hungry as I was that first day. Good luck and hope I can do 20 days. I have not had 1 headache at all, just a little dizzy for like 5 seconds a few times. I did 2 coffee enemas at first and do about one a day now. I think that is what helped me?