water fasting can be a tremendous strain on the body and specially the adrenal glands. I used to Water Fast and ended up with adrenal fatigue and I am having a hard time loosing weight and I am always exhausted and I am under treatment for it. I am told by my naturopath not to Water Fast anymore. Water Fasting should be done during a period of complete rest and stress free environment otherwise it can do more damage than good. Also, a lot of people have already mild adrenal fatigue and they can worsen their condition without knowing.
We live in extremely toxic world, and Water Fasting can be a real stresser on the body. Most Water Fasting books were written at a time where the toxins were much less than right now. Please prepare for your fast and do it at a time when you can completly rest.