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.
Herbert Shelton (1895-1985), the physician who supervised the fasts of over 40,000 people in this century, wrote
Fasting must be recognized as a fundamental and radical process that is older than any other mode of caring for the sick organism, for it is employed on the plane of instinct…
The early great philosophers, thinkers, and healers advocated fasting for health and as healing therapy. Hippocrates, Plato, Socrates, Aristotle and Galen all praised fasting.
Paracelsus, one of the three fathers of Western medicine, is quoted as saying, "Fasting is the greatest remedy--the physician within." Early healing arts recognized the revitalizing and rejuvenating power fasting promoted.
Fasting has been used therapeutically since at least the 5th century BC, when Greek physician Hippocrates recommended abstinence from food or drink for patients who exhibited certain symptoms of illness.
Some physicians recognized a fasting instinct, whereby patients in certain disease states naturally experience a loss of appetite. Some physicians believed that administering food during such states was unnecessary and possibly even detrimental, since fasting was thought to be an important natural part of the recovery process.
Early religious and spiritual groups practiced 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.
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 USA, the groups most noted for continuing fasting traditions are Episcopalians, Roman Catholics, Lutherans and Jews. This cohort of people represents hundreds of millions of people throughout the world, and billions throughout history.
Yogic practices, including that of fasting, date back thousands of years. Yogananda said simply, “is a natural method of healing.” To this day, the ancient healing practice of Ayurveda includes fasting as therapy.