I am a Reform rabbi who has been studying Islam for more than 50 years. Reform Judaism is the largest branch of the three major denominations of Jews in America. I think it is vitally important for our generation to understand how much Islam and Judaism have in common, and fasting is one area where this harmony is evident. In the U.S. and Canada, Jews and Muslims are the religious groups that noticeably practice fasting. There are several religious values involved in fasting; Muslims will see many similarities, and a few differences, in the following teachings from the Jewish tradition.

Don’t most people think that being happy is the most important thing? Isn’t eating one of the most accessible pleasures we have? Why should people limit their culinary pleasures? More outrageous, why should we afflict ourselves by fasting? Why do Islam and Judaism restrict their adherents from the simple pleasure of food each year? For the entire month of Ramadan, Muslims fast from first light until sundown, abstaining from food, drink and marital relations. The Qur’an says, “Oh you who believe! Fasting is prescribed to you as it was prescribed to those before you, that you may (learn) self-restraint” (2:183). Why should the Torah decree for Jews a day of fasting (Leviticus 16:29, 23:27) when for twenty-four hours adult Jews (in good health) are supposed to trouble their bodies by abstaining from eating, drinking and marital relations? Both religions teach us that what we do not eat may be even more important than what we do eat.

All animals eat, but only humans choose not to eat some foods that are both nutritious and tasty. Some people do not eat meat for religious or ethical reasons. Jews and Muslims do not eat pork for religious and spiritual reasons. On fast days such as Yom Kippur—the Day of Atonement and the ninth of Av (a day of mourning like the Shi’a observance of Ashura on the tenth of Muharram)—Jews do not eat or drink anything at all, and abstain from marital relations for twenty-four hours. Fasting results in many different outcomes that help bring us closer to God.

First of all, fasting teaches compassion. It is easy to talk about the world’s problem of hunger, easy to feel sorry that millions of people go to bed hungry each day. But not until one actually feels it in one’s own body does the impact truly hit home. Compassion based on empathy is much stronger and more consistent than compassion based on pity. It is a feeling that leads to action. Fasting is never an end in itself; it has many different outcomes. But none of the other outcomes are of real moral value if compassion is not enlarged and extended through fasting. As the prophet Isaiah said, “The truth is that at the same time you fast, you pursue your own interests and oppress your workers. Your fasting makes you violent, and you quarrel and fight. The kind of fasting I want is this: remove the chains of oppression and the yoke of injustice, and let the oppressed go free. Share your food with the hungry and open your homes to the homeless poor” (Isaiah 58:3-7).

Second, fasting is an exercise in will power. Many people think they can’t fast because it’s too difficult, but actually the discomfort of hunger pangs is relatively minor. A headache, muscle soreness from too much exercise, or a toothache are more severe than the pain temporary hunger produces. I have on one occasion fasted for three days, and found that after the first twenty-four hours the pain decreases slightly, as the stomach becomes numb. The real reason it is challenging to fast is because it so easy to break the fast, since food is almost always in easy reach — all you have to do is take a bite. Thus the key to fasting is the will power to decide again and again not to eat or drink. Our society has increasingly become one of self-indulgence; we lack basic self-discipline. Fasting opposes our increasing “softness” in life; when people exercise their will power to fast, they are affirming their self-control and celebrating mastery over themselves. We need continually to prove to ourselves that we can do it, because we are aware of our frequent failures to be self-disciplined.

The third outcome of fasting is improved physical health. Of course, one twenty-four hour fast will not have any more effect than one day of exercise; only prolonged and regular fasting promotes health. The annual fast on Yom Kippur can, however, awaken us to the importance of how much and how often we eat. For many years, research has shown that when animals are slightly underfed, receiving a balanced diet below the normal quantity for maximum physical health, their life spans were prolonged from 50 to 100 percent. With all the additives placed in food these days, a reduction of total food intake is healthful. More important, since our society has problems with overabundance, fasting provides a good lesson in the virtue of denial. Illnesses caused by overeating are increasing in affluent Western countries, such as the incidence of diabetes. Sixteen million people in the United States have diabetes, according to the U.S. Centers for Disease Control and Prevention.

Diabetes can lead to blindness, kidney disease, heart disease, nerve damage, amputation and sometimes death. The prevalence of the disease is related to high rates of obesity and sedentary lifestyles, which increase the risk of developing the disease. More than half of adults in Los Angeles are overweight, and 60 percent do not get regular exercise. One-fifth of all those who are obese will develop diabetes. Thus going without any food, or even water, for a twenty-four hour period challenges us to think about the benefits of the spiritual doctrine “less is more.”

Fourth in our list of outcomes is that fasting is a positive struggle against our dependencies. We live in a consumer society, and are constantly bombarded by advertising that tells us we must have this or that to be healthy, happy, popular, or wise. By fasting, we assert that we need not be totally reliant on external, material things, even essentials such as food. If our most basic need for food and drink can be suspended for twenty-four hours, how much more may we learn to limit our needs for all non-essentials? Judaism and Islam do not advocate asceticism as an end in itself; in fact, it’s against Jewish and Muslim law to deny ourselves normal physical pleasures. But in our overheated consumer society, it is necessary periodically to turn off the constant pressure to consume, and forcibly remind ourselves that “Man does not live by bread alone” (Deuteronomy 8:3).

Fifth, fasting serves as a penance. Though self-inflicted pain may alleviate some guilt, it is much better to reduce one’s guilt with offsetting acts of righteousness. This is why charity is an important part of Yom Kippur, and the same is true for Muslims during Ramadan. Indeed, Judaism teaches that fasting which doesn’t increase compassion is ignored by God. The concept of fasting as penance helps us to understand that our hunger pains can be beneficial. Contemporary culture desires happiness and comfort above all else. Any pain or suffering is seen as unnecessary, even evil. Though we occasionally hear people echo values from the past that suffering can help one grow, or that an existence unalloyed with grief would lack certain qualities of greatness, many today think that the primary goal in life is to always be happy and free from all discomfort. The satisfaction one derives from the self-induced pain of fasting provides insight into a better possible reaction to the normal, external suffering we will all experience throughout our lives. Taking a pill is not always the best way to alleviate pain, especially if by doing so we allay the symptoms without reaching the root cause.

Sixth, fasting is good for the soul. It often serves as an aid for spiritual experiences. For most people, especially those who have not fasted regularly before, hunger pains are a distraction. People who are not by nature spiritual or emotional individuals will probably find that a one-day fast is insufficient to induce an altered state of consciousness. Those who have fasted regularly on Yom Kippur might like to try a two- to three-day fast (liquids permitted after the first 24 hours). It is best to go about daily activities and devote late evening or early morning to meditation and prayer. Having already fasted for Yom Kippur, one may simply extend the fast another thirty-six to forty-eight hours. We are prohibited to fast prior to Yom Kippur; eating a good meal prior to Yom Kippur Eve is a mitzvah (religious duty), because Judaism, like Islam, opposes excessive asceticism.

The seventh outcome of fasting is the performance of a mitzvah, which is the one fundamental reason for fasting on Yom Kippur. We do carry out mitzvot (religious duties) in order to benefit ourselves, but because our duty as Jews requires us to do them. Fasting is a very personal mitzvah, with primarily personal consequences. Fasting on Yom Kippur is a personal offering to God, from each and every Jew who fasts. For more than 100 generations, Jews have fasted on this day; fasting is part of the Jewish people’s covenant with God. The principal reason to fast is to fulfill God’s commandment, but the outcome of the fast can be any of a half-dozen forms of self-fulfillment. But simply knowing that one has done one’s duty as a faithful Jew is the most basic and primary outcome of all.

Finally, fasting should be combined with the study of Torah (the five books of Moses specifically, or Scriptural texts in general). A medieval text states, “Better to eat a little and study twice as much, for the study of Torah is superior to fasting.” Indeed, the more one studies, the less one needs to fast. Fasting is a very personal, experiential offering. However, though study is also a personal experience, it takes place with a text and/or a teacher. The Divine will is often more readily and truly experienced in study or in spiritual dialogue with others than in solitary meditation.

May our fasting become a first step toward the removal of the chains of self-oppression and narrow-mindedness that enslave us, our neighbors, and our world! May future years of shared fasting by Muslims and Jews lead to a greater understanding and respect through increased acceptance of religious pluralism. May we always be part of those organizations and movements that are fully committed to contributing to world peace, and who are equally committed to respecting both our own religion and our neighbor’s.

Muslim scholar Fethullah Gulen points out that the Abrahamic faiths (Judaism, Christianity, and Islam) and some non-Abrahamic faiths (Hinduism) accept that there is only One source for all religions, and pursue the same goal. Gulen states: “As a Muslim, I accept all Prophets and Books sent to different peoples throughout history, and regard belief in them as an essential principle of being Muslim. A Muslim is a true follower of Abraham, Moses, David, Jesus, and all other Prophets. Not believing in one Prophet or Book means that one is not a Muslim. Thus we acknowledge the oneness and basic unity of religion, which is a symphony of God’s blessings and mercy, and the universality of belief in religion.” Gulen’s description of universal religion as a symphony is an excellent illustration. One cannot have harmony if everyone plays the same notes; and one cannot have symphony if everyone plays the same instruments. Individual conductors and composers are different, but the source of musical creativity is One. According to a hadith narrated by Abu Huraira, Prophet Muhammad said, “The prophets are paternal brothers; their mothers are different, yet their religion is one (because they all have the same father)” (Bukhari, Book 55, Hadith 652).

Allen S. Maller is the former Rabbi of Temple Akiba in Culver City, California. He has authored several books and is currently the editor of a series of prayer books for the Jewish High Holy Days.