Fasting has existed in human society since the ancient times of pre-history. People have fasted for a multitude of reasons over the centuries, for religion and health most often. Fasting is, in most circumstances, the abstinence from food and drink, sometimes precluding water, sometimes not. Religious fasting is done in different teachings worldwide, and generally follows prescribed rules and observations. Fasting for medical reasons can be advised by a doctor or healer, and other reasons for fasting, like protest, are carried out around the globe in a variety of ways.

In the form of hunger strikes, fasting has evolved as a type of non-violent protest in which participants refuse to eat as a means of achieving political change. Famous fasting protesters include India’s Mohandas Gandhi, the Tibetan freedom fighters of the 21st century, Guantanamo Bay detainees, and Bobby Sands, the Irish Republican paramilitary prisoner who fasted for 66 days before dying in the 1981 Provisional IRA Hunger Strike. Fasting is used in protest as a means of gaining attention and evoking feelings of guilt.

Medical fasting is carried out to cleanse the body, to clear out the digestive systems, or to free the body of unnatural substances, and is often used prior to many medical procedures. Because of the negative reaction of food in a person’s system with anesthesia before a procedure, it is often suggested to fast for at least 12 hours before. Fasting as a means of improving the health of a person is best used under medical instruction, often with only water, and should be followed by a proper diet. This type of fasting can help to eradicate germs and disease from the body, and is often a popular cleansing method.

Fasting is used in many religious contexts by many different religions. It is practiced as a means of penance and in many faiths is required of devout followers. Adherents of the Baha’i Faith fast as a recuperation towards prayer and meditation. Buddhist fasters refrain from food so as to deny themselves the pleasures of the flesh that was denied their gods. Hindus who fast offer their fast as a sacrifice to god, while fasting in Jewish cultures is seen as an atonement of sins and a form of commemorative mourning. Muslims fast between sunrise and sunset for the entire holy month of Ramadan as a way to prevent sins, develop good behavior, and induce a sense of fraternity and togetherness.