1. On Yom Kippur, a person is liable for eating [an amount of] food that is fit for humans to eat¹If, however, the foods are not fit for human consumption, different rules apply. (See Halachah 5.) and is equivalent to the size of a large ripe date²Although most prohibitions against forbidden foods involve a smaller measure - a k'zayit (the size of an olive) - an exception is made in this instance, because a person's appetite will not be sated if he eats an amount of food smaller than the size of a date. In contrast to the measure for drinking, this is a standard measure, regardless of a person's size (Yoma 80a). - i.e., slightly less than the size of an egg.³According to Shiurei Torah an egg is 57.6 cubic centimeters; according to Chazon Ish (when the smaller measure is more stringent), it is 41 cubic centimeters. Thus, the size of a date would be a slightly smaller figure. The laws regarding eating less than this amount are mentioned in Halachah 3. All foods [that one eats] are combined to produce this measure.

Similarly, one who drinks a cheekful of liquid fit to be drunk by humans is liable. The size of a cheekful is [not a standard measure,] but rather dependent on the size of the cheek of every individual.

What is meant by a cheekful? Enough [liquid] for a person to swish to one side of his mouth and for his cheek to appear full. For an ordinary person, this measure is less than a revi'it.⁴The commentaries interpret this to mean slightly less than a revi'it. Note, however, the Shulchan Aruch (Orach Chayim 271:13), which states that this measure is slightly more than half a revi'it with regard to the laws of kiddush. (Note the comments of the Be'ur Halachah 271.)

All liquids [that one drinks] are combined to produce this measure. Foods and liquids are not combined in a single measure.⁵For this will sate neither one's appetite nor one's thirst (Yoma 81a).

2. One is liable for karet for eating on Yom Kippur if one eats food that is fit for human consumption, regardless of whether it is permitted or forbidden.⁶For even forbidden food will sate one's hunger (Rabbenu Manoach). [This includes] piggul,⁷A sacrifice that was offered with the intent that it - or any of its sacred elements - be offered on the altar or eaten at a time when it is forbidden to be eaten; e.g., a peace offering the blood of which one thought to have poured on the altar at nightfall, or to have its flesh consumed on the third day after its sacrifice (Hilchot Pesulei HaMukdashim 13:1). notar,⁸Sacrificial meat that was left over past the time during which it is allowed to be eaten - e.g., a sin offering on the morning of the following day or a peace offering on the morning of the third day (Hilchot Pesulei HaMukdashim 18:10). tevel,⁹Produce from which the agricultural requirements of terumah and the tithes were not separated (Hilchot Ma'achalot Asurot 10:19). the flesh of an animal that died without ritual slaughter, the flesh of an animal that is trefah,¹⁰An animal that will not live longer than twelve months, because of a wound or blemish (Hilchot Ma'achalot Asurot 4:6-8; Hilchot Shechitah 5:1). fat, or blood.¹¹By eating from this prohibited food on Yom Kippur, one violates two prohibitions: the consumption of the prohibited food and eating on Yom Kippur (Merkevet HaMishneh). See Hilchot Shegagot 6:4 and the conclusion of Chapter 14 of Hilchot Ma'achalot Assurot.

3. If a person eats or drinks less than the above-mentioned measures, he is not liable for karet. Although the Torah forbids partaking of less than the measure [for which punishment is given], one is not liable for karet unless [one partakes of] that measure.¹²Since the substance that he is eating is forbidden, it is merely lacking in quantity (Rabbi Yochanan's view, Yoma 74a).

A person who eats or drinks less than the minimal measure is given "stripes for rebellion."

4. [The following rules apply when] a person eats a small amount, [pauses,] and eats again: If the time from when he begins eating until he concludes eating is less than the time it takes to eat an amount of bread and relish equal in size to three eggs, [the food that he eats] is included in the same measure.¹³Our translation is based on the Rambam's statements in Hilchot Tu'mat Tzara'at 16:6.

Whenever the Torah mentions a prohibition - and similarly, a mitzvah - that involves eating, the intent is that the person partake of a minimum measure within a specific time. The standard time for all prohibitions (and mitzvot) is כדי אכילת פרס, which the Rambam defines as the time it takes to eat the above amount. [There are opinions that state an amount of bread equivalent to four eggs (Maggid Mishneh). This opinion is mentioned in the notes on Halachah 8.]

In time, כדי אכילת פרס is defined as six minutes by the Tzemach Tzedek in one place and seven minutes in another (Sha'ar HaMiluim, sec. 9). Other opinions mention nine minutes, 8, 7 1/2, 6, 5, 4 1/2, 4. (See Ketzot HaShulchan 3:15.) If not, it is not included in the same measure.¹⁴And it is considered as if the person ate less than the minimum measure. For this reason, as mentioned in the notes on Halachah 8, when a person must eat on Yom Kippur, there are times when at first he is given less than the minimal amount, his eating is interrupted, and then he is given less than the minimal amount again, so as to minimize the extent of his transgression.

[Similar rules apply when] a person drinks, [pauses,] and drinks again: If the time from when he begins drinking until he concludes drinking is less than the time it takes to drink a revi'it,¹⁵I.e., the amount of time it takes to drink a revi'it leisurely (Radbaz, Vol. V, Responsum 1554). This is, nevertheless, a much smaller measure than the amount of time it takes to eat three eggs.

The Ra'avad (in his gloss on Hilchot Terumah 10:3) differs and states that even regarding drinking, the minimum measure is the amount of time it takes to eat three eggs. (Significantly, the source on which his opinion is based, Keritot 13a, is cited by the Rambam as halachah in Hilchot Sha'ar Avot HaTum'ah 8:11.)

Although the Shulchan Aruch (Orach Chayim 612:10) appears to favor the Rambam's view, Shulchan Aruch HaRav 612:15 and the Mishnah Berurah 612:31 suggest following the more stringent view. [the liquid that he drinks] is included in the same measure. If not, it is not included in the same measure.

5. When a person eats foods that are not fit for human consumption - e.g., bitter herbs or foul-tasting syrups - or drinks liquids that are not fit to to be drunk - e.g., fish brine, pickle brine¹⁶Our translation is taken from Rav Kapach's translation of an Arabic term in his edition of the Rambam's Commentary on the Mishnah (Yoma 8:2, Nedarim 6:4). In the latter source, the Rambam also states that the brine is sometimes made from fish. The Mishnah Berurah 612:28 renders the Hebrew term as referring to fat that exudes from a fish. or undiluted vinegar - he is not liable for karet¹⁷When describing the fast, Leviticus 23:29 uses the expression, "Every soul that will not afflict itself shall be cut off." Eating food that is not fit for human consumption is also a form of affliction. Hence, one is not liable for punishment (Rabbenu Manoach). even if he eats or drinks a substantial amount. He should, however, be given "stripes for rebellion."

6. A person who drinks vinegar mixed with water is liable. One who chews dried pepper, dried ginger, or the like is not liable. [If, however, one chews] fresh ginger, one is liable.¹⁸From the fact that the text mentions only fresh ginger, and not fresh peppers, the Maggid Mishneh states that one might infer that one is not liable for eating fresh peppers. He differs with this conclusion and suggests amending the text based on the Rambam's statements in Hilchot Berachot 8:7. The Shulchan Aruch (Orach Chayim 612:8) also makes a distinction between fresh and dried peppers.

A person who eats the leaves of the vine is not liable,¹⁹The Shulchan Aruch (loc. cit.:7) quotes the version of Yoma 81b that we have, which states, "the leaves of reeds." The Rambam's wording is based on the version quoted by Rabbenu Chanan'el. but one who eats the buds of the vine is liable.²⁰I.e., the leaves just as they emerge from the stem of the vine. What is meant by the buds of the vine? The buds that have sprouted in Eretz Yisrael from Rosh HaShanah until Yom Kippur. If they sprouted earlier, they are considered as wood, and the person is not liable. The same rules apply in all analogous situations.

7. When a person eats roast meat that has been salted, the salt is included in the mass of the meat.²¹I.e., when calculating whether or not a person ate a quantity of food equivalent to the size of a date. Similarly, brine on a vegetable is included,²²Although the brine is a liquid, and liquids and foods are not ordinarily combined (Halachah 1), since the brine is used to flavor the vegetable, it is considered to be a food (Yoma 80b). because condiments that make food fit to be eaten and are mixed together with the food are considered to be part of the food.

If a person was already sated [because he] had overeaten to the extent that he was jaded by food, and then ate more,²³The Rambam's wording requires some clarification. He is referring to a person who had overeaten before the commencement of Yom Kippur, and then despite being disgusted by food, continued to eat on Yom Kippur itself (Maggid Mishneh; Shulchan Aruch, Orach Chayim 612:6). If a person began eating in the midst of the fast and then overate, he would be liable, because of the first morsels of food that he ate. he is not liable. It is comparable to a person who eats food that is not fit for consumption. Although this additional amount is fit to be eaten by a person who is hungry, it is not fit for a person who is sated to this extent.²⁴If, however, the person is not jaded with the taste of the food, e.g., because the food is prepared in a very flavorful manner, he is liable even though he overate.

8. When a person who is dangerously ill²⁵Compare to Hilchot Shabbat 2:5, which explains that the classification "dangerously ill" means that "he has a wound in his body cavity, from his lips inward." Such a person does not need the assessment of a physician to determine whether or not the Sabbath should be violated on his behalf. In situations where the seriousness of the person's ailment is not as obvious, the Sabbath may be violated on his behalf based on a physician's pronouncement. Also, in this category is a women within three days after childbirth.

Significantly, when stating this law, the Shulchan Aruch (Orach Chayim 618:1) mentions only "a sick person who must eat," without stating that he must be dangerously ill. The Be'ur Halachah emphasizes that in many instances, even mildly serious conditions can become life-threatening if the person fasts. asks to eat on Yom Kippur, he should be fed²⁶See Hilchot Yesodei HaTorah 5:6, which states that with the exception of the prohibitions against idol worship, murder, and incestuous or adulterous relations, any of the Torah's prohibitions may be violated to save a person's life. As mentioned in Hilchot Shabbat 2:1, even if there is a doubt regarding the matter, the Sabbath should be violated, and moreover, it should be the leaders of the people and the wise who violate the Sabbath on the sick person's behalf, so that the people at large will appreciate that this is the course of action that should be taken. because of his request until he says, "It is enough,"²⁷Significantly, the Shulchan Aruch (loc. cit.:7) mentions that when a sick person is fed on Yom Kippur, he should first be fed less than the size of a date within the amount of time it takes to eat four eggs (the more stringent view regarding the time of כדי אכילת פרס). If, however, that is not sufficient, the more lenient opinions concerning the measure of כדי אכילת פרס can be relied upon. If even that is not sufficient, the person should be fed in the normal manner. even though expert physicians say that it is unnecessary.²⁸The sick man's own opinion should followed, because "the heart knows the bitterness of his soul." Nevertheless, the person should be reminded that it is Yom Kippur. If he persists in his desire to eat, we assume that he does not desire to transgress, but cannot bear the fast (Shulchan Aruch HaRav 618:1; Mishnah Berurah 618:5).

When the sick person says that it is unnecessary for him to eat,²⁹This is speaking about a person who genuinely does not think that it is necessary for him to eat. It must be emphasized that the Rabbis frowned on the supposed "piety" of a sick person who knows that he should eat, but refrains from doing so because of the fast, and applied the verse (Genesis 9:5 : "I will demand an account of the blood of your own lives" (Mishnah Berurah, loc. cit.). He should be forced to eat, even against his will. and a physician says that it is necessary, he should be fed according to [the physician's] instructions, provided the physician is an expert.³⁰The Mishnah Berurah 618:1 quotes opinions that state that a Jew need not be an expert physician to render such an opinion. Since he is aware of a threat to life and knows the seriousness of Yom Kippur, his view is accepted. A gentile, however, must be an expert physician for his view to be considered.

When one physician says that it is necessary [for a sick person to eat], and another physician says that it is unnecessary, the person should be fed. If several physicians say that it is necessary [for a sick person to eat], and other physicians say that it is unnecessary, [the ruling] follows the majority, or those with the most expertise.³¹The Shulchan Aruch (Orach Chayim 618:4) differs and states that if two physicians say that the sick person should eat, their opinion should be followed. Since two physicians have made such a statement, no further risks should be taken with a person's life. [This applies] provided the sick person does not himself say that it is necessary [for him to eat]. If, however, he makes such a statement, he should be fed.

If the sick person does not say that he must [eat], the physicians were divided on the issue, they were all experts, and an equal number took each side, he should be fed.

9. When a pregnant woman smells food, [and is overcome by desire for it,] we should whisper in her ear that today is Yom Kippur.³²Rabbi Yehudah HaNasi gave this suggestion when asked regarding such a problem (Yoma 83a). If this reminder is sufficient to calm her senses, it is desirable; if not, she should be fed until her desire ceases.

Similarly, if a person is overcome by ravenous hunger,³³This refers to a sense of infirmity that overcomes a person because of lack of nourishment; he becomes, dizzy, faint, and unable to focus his eyes. he should be fed until he sees clearly. He should be fed immediately, even if it necessitates giving him non-kosher meat³⁴If all that is immediately available is non-kosher food, he should be fed food that involves a prohibition that is least severe first. [See Hilchot Ma'achalot Asurot 14:17, the Rambam's Commentary on the Mishnah (Yoma 8:4), and the Shulchan Aruch (Orach Chayim 618:9). See the Noda BiY'hudah, Vol. I, Orach Chayim, Responsum 36, which focuses on this issue.] or [meat from a] loathsome species.³⁵The intent is non-kosher species. Even if their flesh is tasty, they are considered loathsome by Jewish law. We do not require that he wait until permitted food becomes available.

10. [From the time] a child is nine or ten years old³⁶The Shulchan Aruch (Orach Chayim 616:2) explains that when a child's constitution is strong, his training to fast should begin at age nine. If he is weak, the training can be postponed a year. [onward], he should be trained [to fast] for several hours. What is implied? If he is used to eating two hours after daybreak, he should be fed in the third hour. If he is used [to eating] after three hours, he should be fed in the fourth. According to the child's stamina, we should add hours to his anguish.

When a child is eleven years old, whether male or female,³⁷The Ra'avad differs and maintains that since males and females reach maturity at different ages, that factor should be taken into account in this law. According to his view, a male child is not obligated to complete the fast until he is twelve, and a female must complete the fast at age eleven.

The Shulchan Aruch (Orach Chayim, loc. cit.) quotes the Rambam's view. The Ramah mentions a third opinion, which does not require children to complete a fast at all. He states that when a child's constitution is weak, this view should be followed. it is a Rabbinic ordinance that he complete his fast so that he be trained in [the observance of] the mitzvot.

11. A female who is twelve years old and one day³⁸Even a fraction of a day is considered to be a day. Therefore, if a girl's birthday is on Yom Kippur, she is obligated to fast from her twelfth birthday onward. and a male who is thirteen years old and one day, who manifest [signs of physical maturity - i.e.,] two [pubic] hairs, are considered to be adults with regard to [the observance of] all the mitzvot, and are obligated to complete their fast according to the Torah. If, however, they did not manifest [signs of physical maturity], they are still considered to be minors, and are obligated to complete their fast only by virtue of Rabbinic decree.³⁹In this instance, however, even a child with a weak constitution should make every effort to complete the fast. For it is possible that the child had pubic hairs, which would cause him or her to be considered to be an adult, but they fell off (Ramah, Orach Chayim 616:2).

A child who is less than nine years old should not be afflicted at all on Yom Kippur, lest this lead to danger.⁴⁰Even if a child desires to fast, he should be prevented from doing so (Ramah, Orach Chayim, loc. cit.).