1) What specifically is forbidden on Yom Kippur?
In addition to the forms of work (both Torah and Rabbinic) that are forbidden on Shabbat, there are five additional prohibitions. They are:
- Eating and drinking
- Applying oils
- Wearing shoes
- Marital relations
2) Should children try to fast all day?
It is assumed that children are not strong enough to fast all day until they are bar/bat mitzvah, and they should not attempt to do so.
Healthy children from the age of nine should be trained to fast part of the day by giving them their meals at a later time than usual, both at night and during the day. Below this age, children should eat as usual.
3) May children eat any quantity or type of food?
Since children are exempt from fasting, there is no restriction to the quantity of food that they may eat. One may give them Yom Tov meals and treats in honor of the day.
4) What are the laws of fasting for a woman who has recently given birth?
For the first 72 hours following the birth, she is forbidden to fast. Even if both she and the doctor agree that she is strong enough to fast, she must eat.
If she says that she does not need to eat, she should eat only small quantities. If during the fast she feels that she needs to eat normally, she may do so.
If she is unsure whether she needs to eat, and certainly if she feels the need to eat, she should eat normal quantities.
5) What are the rules after 72 hours since the birth?
Between three and seven full days (i.e. from 72 to 168 hours) following the birth, the law is slightly stricter. In every case that she is permitted to eat, she may eat only small quantities, unless there are complications.
If she says that she needs to eat, she may do so even if a doctor says the opposite.
After seven full days she must fast like everyone else unless there is some complication.
6) Is a pregnant woman required to fast?
A pregnant woman must fast like everyone else. It is strongly recommended that she rest as much as possible in order to preserve her strength, even if this means davening little or nothing in shul. Wherever possible, conditions in the home should be arranged to ease fasting, e.g. using fans or air conditioning. The husband should be prepared to help at home during the day to enable his wife to fast. If a doctor fears that fasting may cause a miscarriage (God forbid), she may eat or drink small quantities. A doctor (preferably God fearing) and a rabbi must be consulted.
7) Is a nursing mother allowed to drink if she fears a lack of milk for her baby?
In almost all cases this is unnecessary, especially today when baby formula is available that can be used as a substitute for a short period. It is advisable to accustom the baby to formula a few days beforehand to avoid complications arising on Yom Kippur. In extremely unusual circumstances when a sensitive baby cannot tolerate anything other than the mother's milk, it may be possible to allow the mother to drink small quantities. Such serious matters should be determined only after consultation with a rabbi.
8) May a seriously ill person fast?
A person whose life will or may be endangered by fasting, even in the long term, is absolutely forbidden to fast. To be strict and refuse to eat, putting one's life in danger, is foolhardy and a serious offence. A doctor (preferably God fearing) and a rabbi must be consulted in order to determine the seriousness of his condition.
9) Which types and quantities of food may such a person eat?
He may eat any type of food, including those that he enjoys. There is also no restriction to the quantity of food that he may eat. Nevertheless, he must refrain from foods that are not required for sustenance such as ice cream and candies.
10) When eating is permitted, must kiddush be recited first?
No, there is no requirement to make kiddush, even when Yom Kippur is on Shabbat.
11) Should the paragraph ya'aleh veyavoh be added in Grace After Meals?
Yes. Ya'aleh veyavoh should be recited and the paragraph retzei should also be added if Yom Kippur is on Shabbat.
12) What if a person is not ill but fasting may make him dangerously ill?
He should eat small quantities. This is common with elderly people who have serious health problems. A rabbi should be consulted.
13) What are the limitations for a person who may eat or drink in small quantities?
The maximum quantity of food that may be eaten at one session is 30ml (one fluid ounce). This measurement is a volume and not a weight, and is the same for all types of food. A person who knows (or suspects) that he will need to eat, is advised to prepare in advance accurately measured quantities of food. It is recommended to eat substantially filling foods such as fish or meat, which are more satisfying than lighter foods of the same volume.
The liquid quantity is a cheekful. For an average person this is approximately 35ml (just over one fluid ounce) and for a smaller person this could be 30ml.
The food and drink should be plain, since in this situation the amount of pleasure must be minimized.
14) How often may such a person eat small quantities?
Only as often as is necessary. Further, he must wait nine minutes between the end of one session and the beginning of the next. If a doctor insists that this interval is too long, it may be reduced accordingly. It is permitted to eat and drink at the same session.
15) How should a person who is able to fast take medicine if required?
A person may swallow bitter medicines in tablet, capsule or liquid form, but not if they are pleasant tasting or tasteless. The medicine must not be taken with water. If one cannot swallow the capsule or tablet without any liquid, he should use a bitter tasting liquid. (If the capsule or tablet will still be effective when mixed with water, this is a practical solution since such liquid is usually bitter tasting.)
16) May a person who is fasting taste food and spit it out?
No. It is forbidden to taste the tiniest amount of food, even if he is certain that he will not swallow anything.
17) May a person rinse his mouth?
The laws of Yom Kippur are stricter than the laws of other fasts. It is forbidden to rinse the mouth whether with water or with mouthwash, even if one feels very uncomfortable.
Excerpted from "Guidelines - Yomim Noraim" - 300 commonly asked questions about Rosh Hashana and Yom Kippur (Targum/Feldheim).