08 – The Laws of the Fast

01. The Mitzva to Fast

It is a positive commandment to fast on Yom Kippur, as we read:

And this shall be to you a law for all time: In the seventh month, on the tenth day of the month, you shall deprive yourselves; and you shall do no manner of work, neither the citizen nor the stranger who resides among you. For on this day, atonement shall be made for you to purify you of all your sins; you shall purify yourselves before the Lord. It shall be a Shabbat of complete rest for you, and you shall deprive yourselves; it is a law for all time. (Vayikra 16:29-31)

One who does not fast fails to fulfill a positive commandment and violates a negative one. Even though the mitzva of inui (deprivation) is primarily about refraining from life-sustaining food and drink, it also includes four other prohibitions, discussed in the next chapter.

The mitzva is to refrain from eating even the tiniest amount and from drinking even a drop of water. One who eats or drinks in any amount violates a Torah prohibition. One who knowingly eats the volume of a large date (kotevet) or drinks a cheek-full of water is punishable by karet (extirpation), as we read, “Any person who does not deprive himself throughout that day shall be cut off from his kin” (Vayikra 23:29). If one transgresses unknowingly, he is liable to bring a sin offering. These punishments apply only if one eats or drinks an amount large enough to put his mind at ease, as then he is no longer considered to be experiencing inui. These shi’urim (minimum quantities, namely a cheek-full of drink and a kotevet of solid food) were received by Moshe at Sinai as the amounts that put one’s mind at ease. Still, one who eats or drinks anything at all transgresses a Torah prohibition.[1]

One who eats something that is not generally considered edible – such as leaves, twigs, an extremely sharp spice, or rotten food – does not transgress a Torah prohibition, as this is not the normal way to “eat.” Similarly, one who drinks a non-potable beverage – such as an extremely bitter or rotten liquid – does not transgress a Torah prohibition (SA 612:6-8; Rema ad loc. 9). Nevertheless, all of the above are prohibited rabbinically. Since this person has chosen to eat or drink them during the fast, he has made it clear that from his perspective they are edible or potable. Therefore, it is forbidden for him to eat or drink them. Le-khatḥila one must even avoid consuming less than a shi’ur (MB ad loc. 15).[2]


[1]. The Gemara explains that according to R. Yoḥanan, all Torah prohibitions related to eating apply even to less than a shi’ur, as we read, “You shall eat no fat” (Vayikra 7:23) – even in the smallest amount (Yoma 73b-74a). This is because any amount of eating, even just a tiny amount, may ultimately contribute to the shi’ur for which one is punishable (Ritva; see Tosafot 74a s.v. “keivan,” which explains that the rationale of “it may contribute” reinforces the inference from the verse). In contrast, according to Resh Lakish, eating less than a shi’ur is rabbinically prohibited. The halakha accords with R. Yoḥanan (MT, Laws of Resting on the Tenth 2:3 and Laws of Forbidden Foods 14:2). The Yerushalmi maintains that even Resh Lakish concedes that on Yom Kippur one who eats less than a shi’ur transgresses a Torah prohibition (y. Terumot 6:1). This is based on the verse, “It shall be a Shabbat of complete rest for you, and you shall deprive yourselves” (Vayikra 23:32). We see that one is meant to abstain entirely from anything which will detract from inui (Vilna Gaon).

When it comes to all other prohibitions pertaining to eating, one who eats an olive’s bulk (kezayit) is liable, as a kezayit is the minimum quantity that is considered “eating.” However, on Yom Kippur the criterion is what amount puts one’s mind at ease and negates the state of inui. The Sages have a tradition passed down by Moshe that for food this amount is that of a kotevet, and a cheek-full for drink (Yoma 80a-b).

[2]. Several Aḥaronim write that one who is fed via feeding tube due to a damaged esophagus may continue such feeding on Yom Kippur. They maintain that the prohibition applies only when someone gets pleasure from the taste and from the feeling of fullness that one obtains from food (Ḥelkat Ya’akov, OḤ 52; Nishmat Avraham 612:7 n. 2, based on Eglei Tal, Minḥat Ḥinukh, and others). But this is problematic because, in fact, this person does not experience inui, and the Torah does not directly command us not to eat or drink, but to experience inui. It seems, therefore, that one who is fed this way violates a rabbinic prohibition because he has negated the experience of inui, albeit in an irregular way (shinui). Maharsham (1:124) is of a similar opinion. Ḥatam Sofer OḤ 127 seems to say that one fed in this way violates a Torah prohibition as he does not experience inui. Aḥiezer 3:61 limits Ḥatam Sofer to cases where one derives pleasure from ingestion. Nevertheless, it seems to me that since the person ingests food in an irregular way, the prohibition is rabbinic.

Some claim that one may not take pills before Yom Kippur to ease the fast, as the mitzva is to experience inui, and doing this negates that experience (minority opinion in Sdei Ḥemed; R. Ḥayim David Halevy, Mayim Ḥayim 2:40). However, the leading view is the permissive one, since these pills have only a mild effect in creating a feeling of satiety. Their purpose is the same as eating before the fast, namely, to minimize the difficulty of the fast (majority opinion in Sdei Ḥemed; Ḥelkat Ya’akov 2:52; Tzitz Eliezer 7:32:4; Yabi’a Omer 9:54). Nevertheless, it would seem to be prohibited to take pills before Yom Kippur which make one feel especially good (such as strong painkillers which contain opioids), if the purpose is to alleviate the inui. However, one who must take such pills for medical reasons, to avoid severe pain, may take them before the fast and even on the fast (without water). Even though they alleviate some of his suffering, this is not his intention; this will be explained in the next section, in the discussion of caffeine pills.

02. The Sick Who Are Not at Risk

One who is sick and suffering may not eat or drink on Yom Kippur unless the illness is life-threatening, as fasting on Yom Kippur is a Torah obligation, overridden only by risk to life. In this Yom Kippur differs from other fasts; the sick are exempt from fasting on Tisha Be-Av, and on minor fasts pregnant or nursing women are exempt (Peninei Halakha: Zemanim 10:2-4).

Therefore, one who has a flu or the like must fast on Yom Kippur, since these conditions are not life-threatening. It is better for a sick person to stay in bed all day and not go to the synagogue, rather than drink even a tiny amount to enable him to go, for fasting is the main mitzva of the day, through which God purifies the Jewish people of their sins. While lying in bed, one should do his best to pray. If it is difficult for him to read from the maḥzor, he should offer heartfelt personal prayers. But he must not eat or drink. Likewise, a husband whose wife is pregnant or nursing, and in her condition she cannot both take care of the children and fast, should stay home and take care of the children so that his wife can fulfill the Torah’s mitzva of fasting. Her fasting is more important than his praying with a minyan in the synagogue.

One who is sick and suffering may swallow medications in pill form, as long as it does not taste good. He should take the pill dry, and if he is unable to do so, he should either chew the pill or add a little soap to the water he swallows it with, thus ruining the taste.

If fasting causes someone terrible pain, he may swallow painkiller pills. Thus, one who is suffering from caffeine-withdrawal headaches may take a caffeine pill or a painkiller. Similarly, a migraine sufferer may take a pill to prevent the onset of a migraine.[3]


[3]. The Sages forbade taking medicine on Shabbat, lest it lead one to pulverize herbal ingredients to prepare medication. The poskim disagree as to whether this applies to medications produced today by factories as opposed to individuals. In practice, if one is really suffering, he may take pills; if he is just experiencing discomfort but not real pain, it is forbidden (Peninei Halakha: Shabbat 28:4-5, n. 3). One may also take pills that are taken regularly, such as sleeping pills and medications that must be taken for several consecutive days (ibid. 28:6).

The same applies to Yom Kippur. Though we have learned that the Sages forbade eating foul-tasting things on Yom Kippur, in this case, where the purpose of ingestion is not to eat but to take medicine or alleviate pain, the prohibition does not apply (Igrot Moshe OḤ 3:91; Minḥat Shlomo 2:58:25; SSK 39:8). One who suffers severe caffeine withdrawal and has no pills containing caffeine may swallow coffee grounds. Since their taste is extremely bitter, they have the same status as medicine.

One who is in pain and needs medicine that tastes sweet must add something bitter to it to ruin its taste and then swallow it. It is preferable to mix in the bitter substance before Yom Kippur. If only the coating of the medicine is sweet, and, medically speaking, it will not lose its effectiveness if crushed, he should crush it; the bitter taste of the medicine from the inside will ruin the flavor of the coating, and it may all be swallowed. This does not violate the prohibition of grinding, as grinding something that has already been ground is not considered toḥen (Peninei Halakha: Shabbat 12:1).

One who suffers migraines must still fast, even though fasting may trigger a miserable headache, since it entails no threat to life. It is important to realize that, in most cases, there are medications that can prevent the onset of a fasting-induced migraine. In rare cases, a migraine can trigger a stroke, which is indeed life-threatening. One is in this risk category, and thus exempt from fasting, if three conditions are met: 1) He has been diagnosed with fasting-induced migraines; 2) the migraine is preceded by an aura (symptoms that precede a migraine headache) that lasts over an hour; 3) there is no medication (like suppositories or sprays) that can prevent the migraines. Since the patients do not need to eat much at once to prevent the migraine, he should eat and drink in minimal quantities (“le-shi’urim”). (This paragraph was written with the help of Dr. Rafi Cayam and Dr. Rachel Herring.)

03. Someone Sick with a Life-Threatening Illness

Someone for whom fasting is liable to cause death has a mitzva to eat and drink as needed, since saving life overrides the mitzva of fasting – and all mitzvot in the Torah – as we read, “You shall keep My laws and My rules, by the pursuit of which man shall live; I am the Lord” (Vayikra 18:5). Our Sages infer: “‘By which man shall live’ – and not die” (Yoma 85b). The mitzvot were given to promote life, not to cause death (Peninei Halakha: Shabbat 27:1 n. 1). If one is uncertain whether his life is in danger but is “stringent” and does not eat and drink, he is a sinner, as he violated the Torah’s commandment to preserve his life. Of him, the Torah says (Bereishit 9:5), “But for your own life-blood I will require a reckoning” (Bava Kama 91b).

Permission to eat is not limited to cases of grave danger. Rather, as long as there is a chance that fasting will cause a person’s death or weaken his ability to fight off an illness that afflicts him, it is a mitzva for him to eat and drink as needed. Even if someone is already gravely ill, if fasting will likely hasten his death, it is a mitzva for him to eat and drink as necessary, for it is permitted to eat and drink on Yom Kippur even to extend life temporarily.

On the other hand, this should not be taken too far by worrying about remote concerns, for if we were to view every routine illness as possibly life-threatening, it would render moot the halakha that someone sick is obligated to fast on Yom Kippur. Furthermore, anyone with the flu would need to be hospitalized, or at least have a doctor check on him twice a day. Were we really to worry about such levels of risk, we would have to forbid travel by car or plane. Certainly, we would have to prohibit cars that have not passed inspection within the last month. We would also have to prohibit hiking and many other activities.

Rather, the principle is that any danger that people normally treat with urgency and on which they spend time and resources – like rushing someone to the hospital in the middle of a workday – is considered life-threatening. To prevent such danger, it is a mitzva to desecrate Shabbat and to eat and drink on Yom Kippur. However, a danger that people do not normally address immediately with the expenditure of time and resources is not considered life-threatening.[4]


[4]. This criterion is imprecise because some people worry more, and others are more nonchalant. This finds expression in all aspects of life: driving style, attitudes toward illness, planning trips, and, consequently, when to rush someone to the hospital. Each person must use his best judgment, as long as it is within the realm of the reasonable. But if one knows that he is an outlier, he must decide based on what he knows most people would find reasonable.

One who wishes to be stringent and fast even when it is dangerous is not doing a mitzva but rather a sin. One might mistakenly think that this is comparable to a case in which a non-Jew, for his own pleasure, orders a Jew to transgress. In that case, the Jew is not required to sacrifice his life to avoid transgressing, but he may choose to do so in order to sanctify God’s name (Tosafot, Avoda Zara 27b, s.v. “yakhol,” even though Rambam in MT, Laws of Torah Principles 5:1, disagrees and writes that he may not choose death). In our case (of someone dangerously ill), all agree that he may not fast, as doing so does not involve any element of sanctifying God’s name. Rather, just as God commands him to fast, here He commands him to take care of his health.

04. Who Determines Danger?

These halakhot are generally addressed to doctors, who must determine, based on their medical expertise and experience, when there is concern of endangerment, and when there is not. The problem is that many doctors, whether out of excessive caution or lack of respect for the mitzva of fasting on Yom Kippur, always tell anyone who is sick to eat and drink. Some doctors mistakenly believe that if they tell a sick person to eat or drink only minimal quantities (le-shi’urim), there is no prohibition. In truth, the Torah forbids eating and drinking even in small quantities. Only in the case of a patient deemed dangerously ill enough to eat and drink is it preferable, when possible, to eat and drink le-shi’urim (as explained in the next section).

Therefore, questions about fasting must be posed to a God-fearing doctor. This does not mean asking a doctor who wears a particular type of head-covering; rather, the doctor must be moral and ethical, and reach decisions responsibly, factoring in both the sanctity of the day and the sanctity of human life. Patients have the responsibility to approach the doctor out of reverence for God, for if they pressure the doctor to permit them to eat and drink, they are putting the doctor in a very difficult position: He already bears great responsibility, and they are now making it difficult for him to determine whether they are really at risk, or if they simply want to get out of fasting even though there is no risk to life at all. A critical amount of the doctor’s information comes from patient input, so when a patient presses for a dispensation, the doctor may conclude that he is in bad shape and permit him to eat and drink minimal quantities, whereas if the patient had reported honestly, it may have clarified that the situation is not life-threatening at all. In cases of misrepresentation, responsibility for the erroneous ruling lies primarily with the patient.

A God-fearing doctor who is uncertain as to whether a person must fast should consider: “What would I do on Yom Kippur were I to find out that this person was fasting? Would I be willing to violate Yom Kippur by driving for ten minutes to instruct the patient to eat and drink, thus possibly saving his life?” If the answer is yes, it indicates that the doctor believes that there is a true danger to life, and he should instruct the patient beforehand to eat and drink on Yom Kippur. If, however, despite the responsibility he feels for his patient’s well-being, he would not be willing to drive on Yom Kippur for him, it indicates that the doctor believes there is no real danger to life, and he should instruct the patient to fast. This suggestion is effective for the average doctor, who is not lazy but also prefers not to rush from one patient to another.

If a patient mistakenly consulted a doctor who is not God-fearing, and the doctor instructed him to eat and drink, then the patient must make every effort to ask a God-fearing doctor before Yom Kippur. If the patient did not ask, and Yom Kippur has begun, he should eat and drink. Although we are uncertain whether the doctor answered in accordance with halakha, it nevertheless remains a case of uncertainty (safek) in which life is at stake. We therefore are stringent and instruct the patient to eat and drink.

It is important to know that even though these halakhic decisions are in the hands of doctors, if a patient thinks that his life may be in danger, and that eating and drinking can save him, then even if the doctors disagree, he should eat and drink. This is because sometimes a person can sense the gravity of his condition more than doctors can, as it is written, “The heart alone knows its bitterness (Mishlei 14:10)” (Yoma 83a; SA 618:1). However, if the patient says he must eat, and the doctor thinks that eating would endanger his life, we pay heed to the doctor (AHS 618:5-6; SSK 39:4).[5]


[5]. With respect to these halakhot, there is no difference between a Jewish and a non-Jewish doctor. The key factor is trustworthiness (MB 618:1). The Gemara (Yoma 83a) and Rishonim (ad loc.) address cases in which the doctors disagree. In practice, if one doctor says the patient needs to eat, and another says he does not, it is a case of uncertainty, and he should eat (SA 618:2). If two doctors maintain that he does not need to eat, and one says that he does, we follow the majority (SA 618:3). If two doctors say he must eat, we listen to them, even if a hundred other doctors say he need not eat (SA 618:4). If the doctors who say he need not eat include those who are clearly more expert, then since that group has both the majority and the greater expertise, we listen to them and require him to fast, even if two doctors say he must eat (Mateh Ephraim ad loc. 3; see MB ad loc. 12).

Accordingly, if conventional medicine dictates that one should fast, while alternative practitioners say he should eat, we disregard the alternative practitioners, and the patient must fast; conventional doctors are considered more expert because they rely on comprehensive research, and they also constitute a majority. However, if the patient is convinced that the alternative practitioner is correct, he may eat. (See Rema 618:4.)

In Peninei Halakha: Shabbat 27:2, I explain that we listen to the patient over the doctors as long as there is some logic to the patient’s claims. However, if the disease and its treatment are known, but the patient demands treatment that the doctors deem ineffective and that entails Shabbat desecration by someone other than the patient, we listen to the doctors (BHL 328:10 s.v. “ve-rofeh”). Likewise, if the patient is known to be excessively fearful, and the attending caregiver is certain that he is not in danger, the patient should not eat. If, despite the doctor’s view, and despite being aware of his own tendency to worry excessively, he remains sure that he must eat, he may act accordingly. (See Tzitz Eliezer 8:15:7:25, which states that sometimes it is permissible for the patient to desecrate Shabbat on his own behalf, even when it would be forbidden for a doctor.)

05. Eating and Drinking Minimal Quantities (“Le-shi’urim”)

If a person is dangerously ill, but, according to the doctor’s instructions, need not eat and drink large quantities urgently, then according to several of the greatest Rishonim he should eat and drink less than the minimum punishable quantities (shi’urim) intermittently, to minimize the prohibition (as we will explain). Although eating or drinking even tiny amounts is prohibited by the Torah, ingesting a full shi’ur increases the gravity of the transgression: Doing so knowingly incurs the punishment of karet (extirpation) and doing so unknowingly obligates him to bring a sin offering. Therefore, ingesting less than a shi’ur is preferable.

However, if there is any concern that eating and drinking this way will cause at-risk patients to neglect the recovery of their strength, they must eat and drink normally. For example, if a postpartum woman is exhausted, it is better that she drink normally so that she can have uninterrupted sleep than that she stay awake to drink small quantities intermittently.

Likewise, diabetics whose condition has no stable treatment must be very cautious. If there is concern that eating and drinking le-shi’urim will lead them to be neglectful and not eat as much as they need, they should eat normally. It is also better that they pray in the synagogue with a minyan and eat substantial amounts every few hours, rather than eating minimal amounts over an extended period of time and thus be unable to come to synagogue.[6]

Let us now explain the details of eating and drinking minimal quantities (le-shi’urim). For drinking, the minimum punishable quantity is a mouthful, that is, the interior of the mouth plus one cheek is filled with the liquid. This amount varies from person to person. Therefore, the patient must determine how much water fills his mouth by spitting a mouthful into a cup and marking where the water reaches. Le-khatḥila, he should do this before the fast begins. On the fast, he should drink less than this amount each time.

For solid food, the minimum punishable quantity is the volume of a large date (kotevet) – smaller than an egg but larger than an olive, it is approximately 30 cc or one ounce (SA 612:1-5, 9-10).

These shi’urim also contain a time component. That is, to be punishable, one must eat or drink the requisite shi’ur in the time it takes to eat a half a loaf of bread (akhilat pras). Some maintain that this is nine minutes, and le-khatḥila it is good to follow this opinion. One who must eat and drink more frequently may suffice with a seven-minute break. When it comes to drinking, one may even suffice with a break of one minute, because some maintain that for drinking this is enough of a break (SA 618:7-8). There is no halakhic difference between water and other liquids; therefore, if drinking le-shi’urim suffices for a patient, it is recommended that he drink high-calorie beverages, which may make it unnecessary for him to eat.[7]


[6]. Ramban infers from the Gemara in Keritot 13a that a pregnant woman who is in danger and needs to eat on Yom Kippur should eat less than the minimum punishable quantities. He extrapolates from this case to all sick people and concludes that they should all eat and drink le-shi’urim when possible. This is also the position of Rosh, Hagahot Maimoniyot, Tur, and SA 618:7. On the other hand, Rif, Rambam, and many other Rishonim do not mention the idea of le-shi’urim at all, nor is this mentioned in Yoma. In their view, the Gemara in Keritot does not apply to a pregnant woman on Yom Kippur, but rather to a pregnant woman who needs to eat something prohibited. Indeed, several Aḥaronim write that a dangerously ill person should eat and drink whatever he needs on Yom Kippur, with no limitations (Netziv; Or Same’aḥ; R. Ḥayim of Brisk). Nevertheless, the accepted ruling is that when possible, it is preferable to eat and drink le-shi’urim. This is somewhat difficult to understand, as we know that when it comes to danger to life on Shabbat, we do not instruct people to try to minimize the prohibition by asking a non-Jew or minor to carry out a lifesaving melakha, as we are concerned that it will cause people to be neglectful in their lifesaving efforts (Tosafot). We are also concerned that at a future time, if no non-Jew or child is present, people will waste time looking for them, and in the interim the sick person will die (Ran). Based on these concerns, the Sages teach that one should not try to use a shinui when undertaking lifesaving activities, lest it cause delay or negligence. If, on Shabbat, the Sages do not require people to attempt to downgrade from Torah prohibitions to rabbinic prohibitions out of concern for negligence, why is the accepted ruling to try to minimize the severity of the prohibition, particularly since eating minimal quantities still entails violation of a Torah prohibition? (See Peninei Halakha: Shabbat 27:4-5.)

It seems that since the status of the dangerously ill person is known before Yom Kippur, and we can prepare in advance in an orderly fashion, there is no concern for negligence. On the other hand, it is possible that those Rishonim who do not mention eating le-shi’urim are concerned that precise instructions to minimize the prohibition would adversely affect people’s lifesaving efforts. This provides an answer to a question raised by R. Yaakov Ettlinger. He writes that we permit the sick to eat only precisely what is necessary; anything more than that is biblically prohibited. He then expresses surprise that the poskim do not mention this (Binyan Tziyon §34). We can answer that they do not mention it because in practice it is difficult to establish exactly how much a patient must eat or drink, so to avoid any possibility of endangering life, we permit someone dangerously ill to eat and drink as much as he needs. Hilkhot Ḥag Be-ḥag quotes R. Elyashiv as saying this (ch. 26 n. 33), and it is similar to the ruling that we take care of the sick on Shabbat exactly as we would on a weekday (SA 328:4; see Peninei Halakha: Shabbat, ch. 27 n. 4). It should be noted that there have been tragedies in which diabetics who needed to eat on Yom Kippur did not do so and died as a result. Since many diabetics can function normally, they come to synagogue, but there it is difficult for them to eat le-shi’urim. Some have become weak and, without realizing the danger they were in, ended up passing out and dying. When there is any shadow of a doubt concerning danger, diabetics should eat as usual and then go to the synagogue, as the value of eating le-shi’urim does not take precedence over the value of going to the synagogue.

[7]. For more on “akhilat pras,” see Peninei Halakha: Pesaḥ 16:25 and Peninei Halakha: Berakhot 10:7. There are many opinions about its duration, ranging from 4 to 9 minutes. MB 618:21 says that on Yom Kippur we should be stringent in accordance with the opinion of Ḥatam Sofer and consider it 9 minutes. However, in times of need, one may be lenient and wait 7 minutes, which is longer than most opinions require. (In Peninei Halakha: Berakhot 10:7 I rule that eating a shi’ur within 7 minutes requires a berakha aḥarona.) In terms of drinking, Rambam uses a different criterion: the time it takes to drink a revi’it in a relaxed and continuous manner (MT, Laws of Resting on the Tenth 2:4). This is no longer than a minute. However, SA 618:8 states that le-khatḥila one should be stringent and follow Raavad, who equates drinking with eating. (Accordingly, one should wait 7 minutes.) In times of necessity, it is better to follow Rambam rather than drink more than shi’ur at once.

06. The Psychological Aspect

Sometimes a person becomes so weak on Yom Kippur that he is afraid that he is going to lose consciousness and die. This fear is usually exaggerated, as fasting and the attendant weakness are generally not dangerous. (There are even some serious illnesses for which fasting may be helpful.) Nevertheless, it is possible that a person does have some issue which might make fasting dangerous. Therefore, if someone is so afraid he might die that he asks for food and drink despite the holiness of the day, we give it to him. However, since the need is sometimes simply psychological, we begin by giving him only a little. Sometimes this is enough to calm him and bring about a recovery. If this does not work, we continue giving him small quantities of food, spread out over time (as explained in the previous section). If this, too, does not work, he may eat and drink until he is reassured (SA 617:2-3).

Sometimes just knowing that it is permissible to eat and drink restores a person’s well-being. He calms down and feels able to continue fasting. There is a story in the Yerushalmi (y. Yoma 6:4) about R. Ḥaggi, who became very weak from fasting, but when R. Mana told him to drink, he decided that he could manage, and he continued to fast. Many poskim use this strategy (Kol Bo §69, cited by Beit Yosef 618:1).[8]

On the other hand, we must be very careful not to take danger lightly. If doctors have instructed someone to eat and drink, he should do so joyfully, as he is fulfilling God’s commandment to take care of his health. Hopefully, he will merit long life as a reward for observing this mitzva. Torah giants made it a practice to admonish the sick about this. If they knew that a particular patient was likely to disregard medical advice and fast, thus endangering his life, they would visit him on Yom Kippur to persuade him to eat and drink.


[8]. R. Zevin tells a remarkable story. Once, before Ne’ila, there was a commotion in the beit midrash of R. Ḥayim Halberstam, the Sanzer Rebbe. A rich congregant, desperately thirsty, almost passed out. This rich man was known to be very stingy. At first, some mocked him: “Throughout the year, this wealthy man is unwilling to give a poor person a little water to drink. Let him now experience thirst!” However, when the people standing around realized that he was truly in danger, they went to the dayanim to ask what they should do. The rabbis instructed them to give him a spoonful of water (less than a cheek-full). However, each spoonful they fed him seemed to make him thirstier, until he asked for a cup of water. The head of the beit din, Rav Berish, did not trust himself to rule on this, so he approached R. Ḥayim for a ruling. He interrupted R. Ḥayim’s holy worship, told him the whole story, and asked him what to do. R. Ḥayim said, “Tell him that for each cup that he drinks now, tomorrow he must donate a hundred guilder (a substantial amount) to charity. If he agrees to this, give him as much as he wants to drink.” When the wealthy, weak man heard this ruling, it revived him. He got to his feet, stood up straight, and continued to pray as if he was not thirsty at all (R. Shlomo Yosef Zevin, Sipurei Ḥasidim: Mo’adim, p. 101 [A Treasury of Chassidic Tales on the Festivals, vol. 1, pp. 117-118]).

07. Laws of Eating for Those Who Must Eat

Children and dangerously sick people must recite berakhot before eating and drinking on Yom Kippur. If they eat or drink enough to require a berakha aḥarona, they recite that as well. Someone dangerously ill who is drinking le-shi’urim does not recite a berakha aḥarona, as he drinks less than a cheek-full each time, while a berakha aḥarona is recited only after drinking a revi’it (2.5 ounces or 75 milliliters), which is more than a cheek-full. (See Peninei Halakha: Berakhot 10:10.)

In terms of eating, even one who ate minimal quantities may have to recite a berakha aḥarona, because the shi’ur that obligates a berakha aḥarona is a kezayit, and someone eating le-shiurim on Yom Kippur may eat as much as the volume of a kotevet, which is larger than a kezayit (ibid. 10:5).

As we said above (section 5 and n. 6), it is preferable when possible for the dangerously ill to eat and drink le-shi’urim, but when that is difficult, they should eat and drink normally. For example, a postpartum woman who needs to sleep can eat and drink regularly to help her recovery. Diabetics who are praying with the community should eat and drink normally, so that they can attend synagogue without endangering themselves. Children who eat and drink on Yom Kippur should also do so normally.

People who are eating bread must first wash their hands (netilat yadayim). However, rather than washing to the wrists, they should wash only to the base of the fingers. They should wash each hand twice (Peninei Halakha: Berakhot 2:3, 2:11). One who intends to eat less than the volume of an egg (kebeitza) does not recite “al netilat yadayim.” If he intends to eat more than that, he recites the blessing (Peninei Halakha: Berakhot 2:6).

One who always washes mayim aḥaronim before Birkat Ha-mazon may do so on Yom Kippur as well. If one does not normally do so, he should not do so on Yom Kippur (9:5 below).

One who eats at least a kezayit of bread must recite Ya’aleh Ve-yavo during Birkat Ha-mazon and mention Yom Kippur. If he forgot to do so, he does not repeat it. If Yom Kippur is on Shabbat, he should also recite Retzei, but if he forgot, he does not repeat it.[9] One who is reciting Al Ha-miḥya should mention Yom Kippur. Needless to say, if he forgot to do so, he does not repeat it, since even on a normal Shabbat one who forgot to mention Shabbat in Al Ha-miḥya does not repeat it.

Some say that a dangerously ill person who is eating on Yom Kippur must make “Ha-motzi” over two loaves of bread (leḥem mishneh). Additionally, if it is Shabbat, he must make kiddush before eating. However, according to most poskim, one need not make kiddush or use leḥem mishneh on Yom Kippur, and the halakha follows them.[10]


[9]. According to most poskim, children and the dangerously ill, who eat on Yom Kippur, must recite Ya’aleh Ve-yavo. Since they may eat, and Yom Kippur is a mikra kodesh, this must be mentioned in Birkat Ha-mazon (Maharam; Rosh; Hagahot Maimoniyot; Tur; SA 618:10). However, according to others, Ya’aleh Ve-yavo should not be recited, as the mitzva to recite it applies only when there is a mitzva to eat (Shibolei Ha-leket citing R. Avigdor Katz; Taz ad loc. 10). In practice, Ya’aleh Ve-yavo should be recited, since this is the opinion of most poskim. It does not constitute an interruption, and it includes nothing that is incorrect. However, one who forgot to recite it does not repeat Birkat Ha-mazon, since according to those who maintain that Ya’aleh Ve-yavo is not recited on Yom Kippur, the repeated berakha would be in vain (le-vatala). MA (ad loc. 10) implies this, while Ḥayei Adam, Pri Megadim, and MB ad loc. 29 rule this way explicitly.

[10]. When Yom Kippur coincides with Shabbat, some maintain that a dangerously ill person must recite kiddush before eating (Hitorerut Teshuva 3:407; Hagahot R. Akiva Eger 618:2 inclines this way as well, following the approach that making kiddush where one eats is a Torah requirement). However, according to most poskim, the sick person does not make kiddush, as there is no mitzva to eat on Yom Kippur (SAH 618:18; Ḥayei Adam 145:32; Or Same’aḥ, Laws of the Yom Kippur Service 4:1; Responsa Har Tzvi OḤ 1:155; Igrot Moshe, ḤM 1:39; Yaskil Avdi 8:20; Mishnat Ya’avetz OḤ §59; SSK 39:33; Ḥazon Ovadia, p. 307). Knesset Ha-gedola (OḤ 618, Hagahot Tur 9) states that one must use leḥem mishneh. This is difficult to understand, though, as double portions of manna did not fall before Yom Kippur (since it was forbidden to eat then). One might respond that manna did fall to feed the sick and the children. Nevertheless, most poskim maintain that leḥem mishneh is not required, and this is the conclusion of MA 618:10 and SAH ad loc. 18.

  1. Akiva Eger writes in his responsa (§24) that it is permissible to give an aliya to someone dangerously ill who must eat, as the Torah reading is due to the holiness of the day, not to the fast. However, R. Akiva Eger is uncertain about doing this at Minḥa, as it is possible that its Torah reading was established because of the fast. One who ate le-shi’urim may get an aliya. (See Peninei Halakha: Zemanim 7:11 n. 15, where I write that at Minḥa on fast days, one should not give an aliya to someone who ate more than a shi’ur. However, if such a person was mistakenly called up, he may accept, relying upon Responsa Ḥatam Sofer OḤ §157. Ḥatam Sofer allows this because he feels that on a fast day, the Torah reading is because of the day, not because of the fast. The same ruling applies to someone called up on Minḥa of Yom Kippur.) A long-time ḥazan who has to eat le-shi’urim may continue as ḥazan (Ḥazon Ovadia, p. 351).

08. Pregnant Women

Pregnant and nursing women are obligated to fast on Yom Kippur (Pesaḥim 54b; SA 617:1). They are even obligated to fast on Tisha Be-Av, which is a rabbinic requirement, so certainly they are obligated to fast on Yom Kippur, which is a Torah requirement.

In recent times, some rabbis have been allowing pregnant women to drink le-shi’urim on Yom Kippur, because they believe that women are weaker nowadays and may miscarry if they fast. However, studies in Israel and abroad show that fasting does not increase the risk of miscarriage. In rare cases, fasting during the ninth month may induce labor, but this is not life-threatening. There is also no basis for the claim that people today are weaker than they used to be. On the contrary, people are healthier than they have ever been, whether due to the abundance and variety of available food or due to advances in medicine. Life expectancy has increased by decades. Therefore, there is no reason to be more lenient today than in the past, and the law still applies: pregnant and nursing women are required to fast (Tzitz Eliezer 17:20:4; Nishmat Avraham 617:1).

This means that even pregnant women who throw up, have slightly elevated blood pressure, low hemoglobin, or other normal discomforts associated with pregnancy are obligated to fast on Yom Kippur and are not permitted to drink le-shi’urim. Consulting a God-fearing doctor is only necessary if a woman is in the first few weeks of pregnancy following IVF or going through an especially difficult or high-risk pregnancy. If the doctor says that there is possible danger to the life of the mother or the fetus, then she may drink, preferably le-shi’urim. In contrast, a woman experiencing a normal pregnancy with normal symptoms (even if this includes throwing up) must fast. There is no reason to even ask a rabbi about it. Nevertheless, if a pregnant woman who is fasting feels that her situation has become dangerous, she should eat and drink as needed.[11]


[11]. It should be noted that it is not enough for the doctor to be God-fearing. If the doctor accepts the view that most pregnant and nursing women may drink on Yom Kippur, his determination is not considered legitimate according to most poskim (n. 13 below). Therefore, one may rely only on a doctor who answers in accordance with the view that, as a rule, pregnant and nursing women are not put at risk by fasting, and that only in a few cases of high-risk pregnancies is it necessary for a pregnant woman to eat or drink. See section 4 above, where we explain that the people asking have a responsibility to asks questions in a God-fearing manner.

09. Childbirth and Postpartum

From the moment labor begins, or from the moment a woman must be rushed to the hospital to give birth, she is considered to be dangerously ill, and she must eat and drink as needed. She retains this status for seventy-two hours from the moment of birth. If these seventy-two hours end during Yom Kippur, she may eat and drink as needed until seventy-two hours have passed.[12] As we have seen, it is preferable for anyone dangerously ill to eat and drink le-shi’urim if it will not be harmful. However, if a woman postpartum wants to sleep, and eating and drinking le-shi’urim will make it hard for her to get the rest she needs, then she should eat and drink normally.

From seventy-two hours until a week postpartum, her condition must be evaluated. If it is clear to her and her doctor that she is not at risk, she should fast. If they are uncertain, she should not fast (SA 617:4).


[12]. According to Terumat Ha-deshen §148 (cited in SA 617:4), we count until the end of the third day, regardless of the hour of birth. Thus, if a woman gave birth at any point on the seventh of Tishrei, she must fast on Yom Kippur. However, MB 330:10 states that some Rishonim calculate three days – 72 hours – starting from the exact time of the birth. These include Rosh, Ritva, and Hagahot Asheri based on Behag. This is how we rule in practice (SSK 39:15; Yabi’a Omer 7:53:7).

10. Nursing Women

As we have stated, pregnant and nursing women are obligated to fast on Yom Kippur (Pesaḥim 54b; SA 617:1). True, some contemporary poskim maintain that nursing women may drink le-shi’urim, so that the fast does not cause them to stop nursing. Nevertheless, according to most poskim, nursing mothers must fast on Yom Kippur and even Tisha Be-Av. Even though nursing makes the fast more difficult because of the additional loss of fluids, this is not life-threatening. It does not endanger the baby either, because even if the mother’s milk decreases or dries up, milk substitutes are available. In reality, women who fast are generally able to continue nursing.

Good advice for nursing mothers is to skip every other feeding. This will help them make it through the fast relatively easily. In other words, a woman who normally nurses every three hours should nurse at 10 AM. At 1 PM she should use formula or another substitute, and then nurse again at 4 PM. At 7 PM she should once again use a substitute. This way, she will not suffer too much during the fast, and she will not produce less milk. Some babies will not accept a substitute from their mother, in which case someone else needs to feed them formula.

Nevertheless, if the baby is small, weak, and sickly, and the doctor thinks that the baby has a special need for mother’s milk, and there is concern that if the mother fasts, her milk will dry up or be considerably depleted, she may drink le-shi’urim based on the instruction of a God-fearing doctor (BHL 617:1). However, this is rare; if a nursing mother drinks a lot the day before the fast, her milk will almost certainly not be depleted from fasting. It is even better if, starting three days before the fast, she drinks and sleeps more than usual. This will increase her milk supply. She can also pump in the days before the fast, so the baby will have plenty of milk during the fast, and there is no concern that the mother’s milk will be depleted.[13]


[13]. If there is a reasonable chance that a mother’s milk will dry up or be seriously depleted due to fasting, some permit her to drink le-shi’urim, because, in their view, mother’s milk is necessary for the baby’s survival. (This is cited in the name of Ḥazon Ish.) They add that one should not take into account that good milk substitutes are available nowadays (Halikhot Shlomo 6:2; Si’aḥ Naḥum §36). Others testify in the name of various rabbis that even though the sefarim advise to be stringent, in practice we are generally lenient when questions arise. However, these claims are very difficult to sustain, because even though mother’s milk certainly has beneficial properties, and the prevailing medical view strongly encourages nursing, nevertheless, many women do not nurse at all, and we never hear of doctors being up in arms about this and claiming that nursing is necessary to save the babies’ lives. According to an Israeli national health survey from 2000, 10% of Jewish mothers in Israel do not nurse at all, about 70% nurse beyond one month, partially or entirely, only about 50% nurse longer than three months, and only about 32% nurse longer than six months. It stands to reason that many women who stop nursing do so for their own convenience, to facilitate their professional lives or studies. If these factors are sufficient for women to stop or cut down nursing, and the medical establishment does not strenuously object (as would be expected if this were truly life-threatening), then the facts indicate that cessation of nursing is not seen as jeopardizing babies’ lives.

Furthermore, in the past, infant mortality during the first year was very high, and no good milk substitutes were available. Yet the clear ruling was that nursing women were obligated to fast, even on Tisha Be-Av. How then can we even raise the possibility that nowadays this is life-threatening? Good substitutes are available, and we have never heard of a baby who died because his mother stopped nursing him. Even in the past, when there were no milk substitutes, leniencies were granted only in cases where the baby was sick. We see this in Devar Shmuel §107 (cited in Responsa Ḥatam Sofer 6:23); BHL 617:1; Da’at Torah ad loc.; and Har Tzvi (OḤ 1:201:1 toward the end). Therefore, a nursing mother may drink on Yom Kippur only if there is a specific medical reason that her sick baby needs mother’s milk, and there is a concern that fasting will deplete her supply. Torat Ha-yoledet (ch. 51 n. 11) and Piskei Teshuvot (617:2) incline this way as well.

As we stated, the leniencies stem from times when there were no milk substitutes. Back then, if a mother’s milk dried up, she had to hire a wet nurse. If she did not have money for this, the baby’s life was truly in danger due to the likelihood of malnutrition. Today, milk substitutes are available, so it would seem reasonable to be stringent even with sick babies. In practice, though, the ruling is made by a doctor. If the doctor feels that there is a certain danger to the baby’s life if he cannot have mother’s milk, and there is a reasonable fear that the mother’s milk will dry up as a result of the fast, one can rule leniently. However, if the doctor is one of those who instructs many nursing mothers to drink le-shi’urim on Yom Kippur, then most poskim say one cannot rely on his judgment. Rather, one should ask a doctor who proceeds from the assumption that stopping nursing is not normally life-threatening.

We must add that the possibility that a mother’s milk will dry up due to the fast is remote. Generally, fasting does not force a woman to stop nursing. That is, if one is careful, in the days before the fast, to drink at least three liters a day and sleep for eight (or at least seven) hours a day, it is very unlikely that her milk supply will be depleted. On the contrary, many women report that proper preparation for the fast improves their milk supply; they discover how helpful extra drinking and sleeping are for nursing. Moreover, even if a nursing woman did not prepare properly for the fast, if she drinks and rests a lot after the fast, her milk supply will generally return to normal. (Nevertheless, if a nursing woman is in the process of reducing the number of feedings, or has trouble nursing in general, lack of proper preparation for the fast may make it hard for her to replenish her milk supply.)

To sum up, the Torah commands us to fast on Yom Kippur. The Gemara and poskim explicitly state that a nursing woman is included in this obligation. (Even on the rabbinic fast of Tisha Be-Av, pregnant and nursing women are required to fast.) There is no justification for not observing this mitzva based on the unsupported claim that it is life-threatening for nursing women to fast.

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