The biggest problem with Water Fasting happens to people who suffer from chronic constipation caused by dysbiosis and dysbacteriosis.
Not many of those people attempt water fasting, but if they do, they risk some negative symptoms caused by constipation.
Those are the people who have taken oral Antibiotics , or some other strong medications, usually for longer than 14 days.
Now, before anyone starts water fasting, it is advisable to be on vegan diet for several days, or even on vegetable and fruit juices.
The main purpose of this is to actually cleanse your bowel naturally, so when you start water fast, the only thing inside your bowel should be vegetable fibers.
Even if you are slightly constipated, keeping those fibers inside your bowel for 15 days is not going to cause any serious harm.
some people are so seriously constipated, that even several days of vegan diet, or several days of fruit diet or several days of juicing diet is not enough to clean everything out from the bowel.
Another problem is liver health.
During water fasting, liver may continue dumping small amount of toxic bile into intestines.
That amount causes no harm during normal diet, but once you stop eating, it is only water, bile and digestive juices inside your GI tract.
Even a smallest amount of toxins dumped by liver may cause serious symptoms like pain, headaches, cramps, feeling sick, feeling hungry, feeling bad, etc.
How to prevent those serous symptoms?
The answer is water.
But not only drinking water, also water enema.
If you take one single water enema the first 3 days of your fast, (morning is the best time), you can have an easy fast, with minimum negative symptoms.
water enema can also be taken whenever you experience any bad symptoms.
Most of the bad symptoms are caused by the content of the colon.
If you have toxic bile inside your colon, or any food residues, water enema will take care of that.
Enema is not advisable as a treatment for every single day of a long fast.
Taking it the first three days is OK ... after that, only when really needed.
You can also keep water longer inside your colon (retention enema.).
If the water is clean, it can help you keeping you hydrated.
I know that Shelton was against enema, and I am well aware of several people on this forum who are against water enema.
Still, based on my personal experience and experience of several other people, I would like to recommend it to anyone who has taken many medications during their lifetime, or anyone who suffered from serious constipation, or anyone who suffered from chronic skin problems.
Somewhere in your message, you wrote:
"having heard such good things about longer fasts and chronic skin conditions"
So, good luck with your fast, and do not suffer needlessly, Water Fast is suppose to be a healing journey, not a journey that would cause you more suffering.