It takes around 2 weeks +/- to fully adapt to fasting and it's at this time that the really deep cleansing starts. For me it's also around the time I start noticing the quieting of the mind.
From the Detox stages in the FAQs
The body is completely adapted to the fasting process. There is more energy and clarity of mind. Cleansing periods can be short with many days of feeling good in between. There are days when the tongue is pink and the breath is fresh. The healing work of the organs is being completed. After the detoxification mechanisms have removed the causative agent or render it harmless, the body works at maximum capacity in tissue proliferation to replace damaged tissue. While a short fast will reduce the symptoms, a longer fast can completely heal. Homeostatic balance is at optimum levels. The lymphatic system is clean except for a rare discharge of mucus through the nose or throat. After day 20, the mind is affected. Heightened clarity and emotional balance are felt at this time. Memory and concentration improve.