Dietary > Fasting

List ISHAR Online Sources: Dietary > Fasting


Functional Summary


  • Dietary Regimen

Willing abstinence from, or reduction of consumption of certain or all food, drink, or both, for a period of time.


  • Optimization

Fasting is commonly used for weight loss, cleansing the body, especially prior to medical tests for the purpose of establishing a baseline, or prior to surgery to reduce risk of aspiration pneumonia. It can also serve spiritual or political functions.


  • Universal

Fasting is practiced in many different cultures throughout the world for a variety of reasons including for religious, political, and medical purposes.


Topic Summary

It is impossible to trace any specific origin for fasting, as there is reason to believe that the earliest humans fasted at various points of their existence. Even other animals fast in times of stress, illness, or unease. Fasting has been seen in various cultures for thousands of years and is prominently used for religious purposes. Christianity, Judaism, Islam, Gnosticism, Buddhism, Hinduism, and North and South American Indian traditions, among others, practice fasting in some form.

Fasting has been celebrated for its health benefits by prominent philosophers and healers, including Hippocrates, Plato, Socrates, Aristotle, Galen, and Paracelsus. One oft-claimed benefit of fasting is longevity, though few long-term studies have been attempted on humans. It has also been postulated that intermittent fasting could be an alternative to dietary restriction for the purpose of increasing life spans. Some have used fasting as a means to lose weight, which has been shown to be successful in the short term, but potentially dangerous if taken too far. Additionally, prolonged fasting has been shown to slow metabolism, meaning as soon as one stops the fast, one could gain back the weight lost.

Fasting has also been used for political purposes. Typically, it is used as non-violent resistance for the sake of protest, or to increase awareness with the ultimate goal of effecting policy changes. Mohandas Gandhi’s hunger strikes are a powerful historical example of fasting for political reasons, as are the infamous Irish prisoner fasts.

Research Summary

A great deal of research has been done on the effects of fasting in animals, particularly dogs, mice, and rats. Studies on human subjects have been conducted as well, though safety concerns have made animals the preferred subjects. A controlled trial of fasting and a one-year vegetarian diet on rheumatoid arthritis from 1991 found significant improvement in the diet group after four weeks, compared to the control group. A study published in 2014 sought to verify whether postoperative fasting had any effect on the risk for infection and prolonged hospital stays, concluding that the longer duration postoperative fasts were an independent risk factor for both. Innumerable other studies have been done on the effects of fasting on various functions of the human body at different ages, and under a variety of conditions.  Fasting is generally considered a major health decision, and while the benefits can be significant, caution and clear limits are strongly encouraged.



ISHAR strives to present all of our data in an impartial, informative manner.  Nonetheless, there are always different viewpoints on various topics, and ISHAR encourages users to review the perspectives on other informational sites, then come to their own conclusions regarding what they consider the least biased.  The sites below were chosen to represent a wide spectrum of approaches to this topic, and none are endorsed or promoted by ISHAR itself.