The History of Fasting: From Ritual to Science

Ancient and Religious Roots

Fasting, going without food for a set period, appears across religious traditions going back thousands of years, long before it became a subject of medical study. Islam observes Ramadan, a month in which practicing adults abstain from food and drink from dawn to sunset. Judaism observes several fast days, the most widely kept being Yom Kippur, a single day of complete abstention from food and drink. Christianity has long observed Lent, a weeks-long period historically marked by various forms of food restriction, with specific practices varying by denomination and era. Hinduism and Buddhism each include their own fasting observances, tied to specific days, festivals, or periods rather than a single universal practice. This page describes what each tradition has historically practiced, not why a reader should fast or how to approach fasting as a spiritual practice; that is a separate topic from the medical and scientific history covered below.

Fasting as Early Medical Practice

Fasting's place in medical literature is not a recent development. A 1982 review in the Western Journal of Medicine describes prolonged fasting "for political or religious purposes" as an already-recognized clinical scenario by that point, alongside an overview of fasting's basic physiology and complications (Kerndt et al., 1982) [1]. The 20th century also saw fasting move from an occasional clinical observation into organized practice, in forms ranging from supervised clinical programs to unsupervised commercial ventures with very different safety records.

Supervised Fasting Clinics: Otto Buchinger (from 1920)

According to the clinic's own history, physician Otto Buchinger treated his first patients with his fasting method in 1920 (Buchinger Wilhelmi clinic, 2020) [2], and the clinical tradition he started continues today as Buchinger Wilhelmi. This is a historical fact about when and how a specific clinical tradition began, not a current medical endorsement of its methods.

A Cautionary Case: Unsupervised "Fasting Cures" in the Early 1900s US

Not every early fasting practitioner operated with medical supervision or a safety record to match. Linda Hazzard, a self-titled "fasting specialist" who ran a sanitarium in Washington State in the early 1900s, had at least 14 patients die of starvation under her care between 1907 and 1913 (Washington State Digital Archives, n.d.) [3]. She was convicted of manslaughter in the death of one patient, Claire Williamson, was sentenced on February 7, 1912, and died on June 24, 1938, while attempting a fast cure on herself (Washington State Digital Archives, n.d.) [3]. This case shows the kind of risk that modern clinical guidance on fasting, including supervision and a staged return to eating, is meant to address: see how to break a fast and electrolytes during a fast for what that guidance looks like today. It is a real historical cost of fasting attempted without medical oversight, not a hypothetical one.

The Science Catches Up: From Animal Research to the 2016 Nobel Prize

Scientific interest in fasting's underlying biology grew over the 20th century, building on the clinical literature described above. The 2016 Nobel Prize in Physiology or Medicine went to Yoshinori Ohsumi for discovering the mechanisms of autophagy, a cell-recycling process, using baker's yeast as the experimental model (Nobel Assembly, 2016) [4]. The prize recognized how autophagy works at a molecular level, not any finding about how long a person needs to fast to trigger it. See autophagy and fasting for the full evidence review, including what human studies have, and have not, measured.

The fasting-mimicking diet, a structured low-calorie food program distinct from true fasting, was developed by Valter Longo and colleagues starting in the 2010s. Its protocol and the research behind it are covered on what is a fasting-mimicking diet; this page notes only its place in the historical timeline.

Modern Interest in Fasting Is a Timeline, Not a Verdict

Public and scientific interest in intermittent and prolonged fasting is now widespread. This page is a historical timeline, not an evidence review: what current trials do and do not show about fasting's effects on weight, metabolic markers, and other outcomes is covered on this site's other pages, not here. See what the research shows about fasting and what is fasting for that evidence. A long history of practice, on its own, is not evidence that a practice is safe or beneficial; it is a timeline of human interest, not a verdict on what fasting does.

Safety and Cautions

This is general information, not medical advice. Historical interest and the length of a tradition are not evidence that a practice is safe or effective for any individual today. Talk to a clinician before fasting of any length if you are pregnant, under 18, manage diabetes or blood pressure with medication, or have a history of an eating disorder.