This idea of fasting, goes back to all of the ancient healing centres, that's why people went there. They would make pilgrimage and trek hundreds and thousands of miles to go into the basement of the temples or museum. They would be bathed and Anointed in Oils and begin a process of fasting.
Stonehenge was a place of healing. Avalon (apple orchard) at the memorial, put people on juice fasts.
If people want a clean body, the way you become fast or strong would be a fast.
The beautiful thing...