Fasting has a long history as a symbolic demonstration of religious devotion, act of protest, or commitment to a political cause.  Various so-called "natural health" or "hygienic" practitioners advocate fasting to "cleanse the body" or as a cure-all. Contrary to the teachings of proponents, fasting doesn't "cleanse" or "rest" the liver. If anything, fasting overworks the liver by saturating it with toxins produced by fasting itself.  Fasting can be dangerous, especially when undertaken or supervised by ideologists who are blind to its actual effects.

Fasting is particularly dangerous for children.