The more I think about it, the more I'd bet it's liver detox. Some people say juice fasting is a better idea because water/UT fasts are too stressful to the liver.
I'll bet the Coffee-Enema
[coffee enema] would help a lot with this though. One Coffee-Enema
every day, or even 2-3 times a day is a great liver detoxifier. Maybe get into doing a Coffee-Enema
every day for a few days, and then try another UT fast and see how that goes.
Maybe just a juice / UT fast would be a better idea, because either way you're giving your digestive system a break.
A UT fast needs to be prepared for. You shouldn't just go into it the way I did. I had drank UT for a week or two, and a lot of it, but my diet was kind of normal.
If you juice/UT fast, make sure to keep an eye on urine pH, because if it gets too alkaline it will not be as antibacterial. It should be in the 5-7 pH range, I think.