Water fasting is a type of fasting in which the practitioner consumes only water. One may water fast for a variety of reasons, including medical and religious requirements. Such fasting for prolonged periods poses significant health risks if done improperly. In order to accomplish this process properly, rest as completely as possible while not consuming any food typically within a period from 20 to 40 days or longer in some cases. Supposedly, this process allows the body's energies to be almost entirely concentrated on cleansing and healing.