David Jubb is a fake. He is a liar and a charlatan who entrapts people into his cult by professing to know about nutrition and physiology. He does have a PhD from NYU, but not in any area related to nutrition or physiology. After reading his works, anyone who knew anything about nutrition and physiology would instantly realize he is a fake.
He claims to have been a breatharian for ten years. (living off of nothing but air and his own urine) Humanly impossible.
He promotes things and then sells you the ingredients you need to follow them through. Sounds fishy to me. There is no use for any kind of flushing. The gall bladder, liver and colon all take care of that by themselves.
Molds and yeast do not live in the colon. They are destroyed in the highly acidic stomach long before they reach the colon. Bacteria do live in the colon, but these are neccessary for digestion.

If you wnat to eat better, check out a book from the library written by a main stream nutritionist. They have a much better understanding about what is important for the body that Mr. Jubb.