I too experienced no weight loss and a 1 pound weight gain I finally lost on day 21. I drank ONLY water and was moderately active working, cooking for others, grocery shopping, etc. It is possible not to lose and it is discouraging.
I am stopping at Day 22 because I am so weak have been fairly hungry on and off for over a week. Time for re-entry so I can move on with my healthier lifestyle.