Fasting is a natural practice done to promote healing, to fortify the body and soul, not to tear them down. In the animal kingdom it happens on an instinctual level. It is natural biological action as eating all day is unnatural. Break from the intake of food allows for a rebalancing within the body, and within our psyche, affecting also our sense of connection to the world of spirit. Yogic practices, including that of fasting, date back thousands of years.
Fasting is the simplest way to give the entire body system a time to re-cleanse and rejuvenate. In medical terms, the word 'fasting' can be defined as "voluntary abstinence from consuming food for varying lengths of time. In its simplest form, fasting is abstaining from all food and drink except water and sometimes even water. The history of fasting can't have a beginning point because there's no reason to think that early man did not fast in the normal course of his existence; every other animal, even today, will fast during times of stress or illness, and sometimes even at the slightest uneasiness. It is a natural tendency for the organism, whether human or animal, to seek rest, balance, and to conserve energy at critical times.
Early religious and spiritual groups used fasting as a part of ceremonies and rites--most often during spring and fall equinoxes. Today, every major religion practices fasting for various spiritual benefit.
Besides, fasting has its own relevance in all religions. As per our Hindu scriptures fasting helps create a harmonious relationship between the body and the soul. Hindus believe the denying physical needs are necessary for spiritual gains while Muslims observe fasting during the month of Ramzan considering fasting of utmost importance. Christians believe that fasting helps them to deepen their relationship with God. They also believe that fasting aware them about their spiritual self. Jain religion strongly emphasizes on fasting to purify souls, improve morality, spiritual power, increase knowledge and strengthen relationships.
All medical systems in the world accept and acknowledge the therapeutic benefits of fasting. In our country along with scientific value fasting has been of religious value too and political as well. Christianity, Judaism, Gnosticism, Islam, Buddhism, Hinduism, South and North American Indian traditions--all utilize fasting in one form or another, whether for purification, spiritual vision, penance, mourning or sacrifice. Many faiths prescribe regular fasting to prevent or break the habits of gluttony. In the U.S., the groups most noted for continuing fasting traditions are Episcopalians, Roman Catholics, Lutherns and Jews.