Why Jews Fast on Yom Kippur

Twenty-Five Hours Without Food — And It Means Everything

The 25-hour Yom Kippur fast is commanded in the Torah as part of “afflicting your soul” (Leviticus 16:29) — a physical expression of repentance that strips away bodily needs to focus entirely on spiritual renewal. It is the most widely observed Jewish practice in the world: even Jews who do not attend synagogue regularly, who do not keep kosher, who do not observe Shabbat, will often fast on Yom Kippur. Something about this day cuts through everything else.

Yom Kippur — the Day of Atonement — is the holiest day in the Jewish calendar. From sundown to nightfall the following day (approximately 25 hours), observant Jews abstain from food, drink, and several other physical comforts. The fast is not punishment. It is not a diet. It is an invitation to spend one day living as if the body’s demands do not exist, so that the soul can finally be heard.

The Torah’s Command

The foundation is explicit. Leviticus 16:29-31 states:

“In the seventh month, on the tenth day of the month, you shall afflict your souls… For on this day, atonement shall be made for you, to purify you from all your sins; before the Lord you shall be purified.”

The Hebrew phrase “v’initem et nafshoteichem” — “you shall afflict your souls” — is interpreted by the Talmud (Yoma 73b) as referring to five specific abstentions:

1. No eating or drinking — the core of the fast
2. No bathing for pleasure — washing for hygiene is permitted in limited forms
3. No anointing the body — no lotions, perfumes, or cosmetics
4. No wearing leather shoes — leather symbolizes comfort and luxury
5. No marital relations

These five abstentions work together to create a state of radical simplicity. Stripped of food, comfort, adornment, and physical pleasure, the person who observes Yom Kippur spends the day in a condition that the tradition compares to the angels — beings of pure spirit with no bodily needs.

What Does the Fast Feel Like?

For those who have never fasted for 25 hours, the prospect can seem daunting. Here is what most people experience:

• The first few hours are usually easy. The large pre-fast meal (se’udah ha-mafseket) sustains energy through the evening services.
• Morning can bring headaches, particularly for coffee drinkers experiencing caffeine withdrawal. Drinking extra water the day before and tapering caffeine in advance helps significantly.
• Midday is often the hardest stretch. Hunger, thirst, and fatigue peak. But this is also when many people report that something shifts — the body’s complaints fade into background noise, and a clarity emerges.
• Late afternoon (Neilah service) brings a remarkable surge of energy. The final prayer service of Yom Kippur is often described as the most intense and beautiful of the year. Voices that were flagging find new strength. The sense of communal purpose is electric.
• The shofar blast at the end signals the fast is over. The relief is physical and spiritual simultaneously.

Who Is Exempt?

Judaism is emphatic: the preservation of life overrides the fast. The principle of pikuach nefesh — the obligation to preserve life — takes absolute priority over Yom Kippur fasting. This is not a loophole; it is a core Jewish value. The Talmud states: “Whoever is ill and the doctor says they should eat — they feed them, even on Yom Kippur” (Yoma 83a).

Specific exemptions include:

• Pregnant and nursing women: Many authorities permit or encourage them to eat, particularly if they feel any distress. Sephardi authorities tend to be more lenient than Ashkenazi on this point.
• People with medical conditions: Diabetes, heart conditions, eating disorders, and other health issues may require eating or drinking. A rabbi and doctor should be consulted in advance.
• Children under bar/bat mitzvah age: Children below 12 (girls) or 13 (boys) are not obligated to fast. Many families gradually introduce partial fasting in the years before the child comes of age — perhaps skipping breakfast, or fasting until midday.
• The elderly and frail: Anyone for whom fasting poses a health risk should eat.

When a person must eat on Yom Kippur for medical reasons, they are often advised to eat in shiurim — small measured quantities at intervals — to technically minimize the formal act of eating while still maintaining health.

The Spiritual Logic

Why does repentance require physical deprivation? Several explanations resonate:

• Empathy with the hungry: Fasting reminds the comfortable what hunger feels like. Many communities collect food for the needy before Yom Kippur, and the Haftarah reading (Isaiah 58) explicitly connects fasting with justice: “Is this not the fast I choose — to share your bread with the hungry?”
• Humility before God: Approaching God in a state of physical weakness reinforces the honest truth of the human condition — we are fragile, dependent, mortal.
• Freedom from the body: For one day, the constant cycle of eating, drinking, and satisfying physical needs is suspended. Without these distractions, the mind is free to focus entirely on questions of meaning, morality, and relationship with God.
• Resembling the angels: The Talmud notes that on Yom Kippur, dressed in white and abstaining from physical needs, Jews resemble the ministering angels. This is not arrogance — it is aspiration. For one day, we try to live as beings of pure spirit.

Breaking the Fast

The meal that follows the Yom Kippur fast — called simply “breaking the fast” — is a beloved tradition in its own right. Common foods include:

• Light, easily digestible items like bagels, cream cheese, and smoked fish (in Ashkenazi communities)
• Soups, pastries, and sweet tea (in Sephardi communities)
• Orange juice or sweet beverages as the first thing consumed

Most rabbis advise breaking the fast gently — starting with liquids, then light foods — rather than diving into a heavy meal. The body has not processed food in 25 hours and needs a gradual reintroduction.

Frequently Asked Questions

What if Yom Kippur falls on Shabbat — do Jews still fast?

Yes. Yom Kippur is the only fast day that is not postponed when it coincides with Shabbat. (Other fasts, like the Fast of Esther, are moved if they fall on Shabbat.) The holiness of Yom Kippur supersedes even the Shabbat obligation to enjoy food and drink. When the two overlap, the day carries an especially solemn and elevated atmosphere.

Can you brush your teeth or swallow saliva on Yom Kippur?

Most authorities prohibit brushing teeth with water on Yom Kippur, as there is a risk of swallowing water. Swallowing your own saliva is permitted — it is not considered drinking. Some people use a dry toothbrush or simply rinse their mouth without swallowing. The customs vary, and many people consult their rabbi for guidance.

Is it true that Yom Kippur is the most observed Jewish practice worldwide?

Multiple surveys support this. Studies consistently show that Yom Kippur fasting (or at least partial fasting) is observed by a higher percentage of Jews worldwide than any other single practice — including Passover Seder attendance, Shabbat candle lighting, or synagogue membership. In Israel, even secular Jews who eat non-kosher food year-round will fast on Yom Kippur. Something about this day reaches Jews who are otherwise disconnected from observance.

One Day as Angels

There is something profound about voluntarily choosing discomfort. In a culture that tells us to satisfy every craving instantly, the Yom Kippur fast is almost countercultural — a full day of saying “not now” to the body so the soul can speak. It is not comfortable. It is not supposed to be. But by the time the shofar sounds and the fast ends, most people feel something they did not expect: not just relief, but clarity. A sense that for one day, they were fully present — hungry, thirsty, and completely alive.

That is the gift hidden inside the affliction. And it is why Jews keep coming back to it, year after year, century after century.