TheCph,
"how does herbal tea intertwine with water fasting"?
Not very well, but this type of question has been answered on many an occasion before now on the forum.
Water-only fasting will conserve food reserves, and this includes vitamins/minerals/enzymes and so on to their maximum in the prevention of a deficiency disease.
However, if anything is taken other than water, then deficiency diseases are a very real risk and starvation may become apparent much sooner than would otherwise be the case................... http://www.soilandhealth.org/02/0201hyglibcat/020127shelton.III/020127.ch18.htm