My Dr has told me to eat and drink with Shiurim on Yom Kippur. I have a few questions. Are tablets included in the Shiur? Can I take vitamins? Can I brush my teeth? I know that food goes by volume and not weight. I saw somewhere that a cracker would be allowed somewhere in the region of 10g -13g, is there somewhere where I can find more details eg a quarter of a medium sized apple?
Shalom, May you be blessed with only good health, and a good year. The laws of eating and drinking in shiurim, "measures" on Yom Kippur only apply to those who must eat for serious health reasons, as it appears in your case when you are under doctors orders to eat. The way to do this is to drink less than a cheeks full of liquid (in an average size person around 40ml) (at most) every 9 minuets (some say every 7 minuets, and in cases of need every 4 or even 2 minuets). Food should be eaten less than 44ml in the same time span. Food and drink may both be consumed in the same time span. Tablets are not considered food, and if needed for health reasons they are not included in the measure. So, in your case you should ask the doctor how much food and liquid you need for your health, then consume it over the course of Yom Kippur, in small measures (less than 40ml drink, and less than 44ml of food) every 9 minuets. If this is not enough, you may lessen the time, and consume the food every 4 minuets – or even every 2 minuets if there is such a pressing need. I include here a copy of a technical article from the Star-K website that explains this law very well – VI. Cholim - Shiurim For One Who Is Ill On Yom Kippur A. Food - Someone whose life may be in danger by fasting on Yom Kippur is obligated to eat. Not all cholim (=sick people) who are obligated to eat on Yom Kippur have the same halachic dispensation. There are cholim (who may be in danger) whose illness only warrants minimal eating or drinking. Minimal consumption is termed pachos mi’keshiur (or eating in "shiurim") - below the minimal portion that qualifies for halachic eating and/or drinking. What is pachos mi’keshiur for eating and drinking? On Yom Kippur the pachos mi’keshiur requirement is the volume of food that is less than a koseves hagasa, a type of large date. The volumetric measurement of a koseves hagasa is more than 1.5 fl. oz. (44 ml). Therefore, one who is ill (as above) may eat 1.5 fl. oz. (which is less than a koseves hagasah) of food every nine minutes. A practical way for the patient to do this is as follows: Fill 1 and a 1/2 "shnapps cups" that are marked "1 oz. - 29 ml" with compacted bread, crackers or cereal, and consume that amount every nine minutes. Note: If it is determined that this amount is insufficient and one's life may still be in danger, the patient must eat as much as necessary, even if it is more than the shiur of volume and less time than kidei achilas pras. B. Beverages on Yom Kippur - The minimal volume for beverages that qualifies for pachos mi’keshiur (minimal consumption by a choleh whose life may be in danger) is less than a m’lo lugmav, a cheekful of liquid. Unlike food, the shiur of liquids differs with each individual's capacity to hold liquid in his or her mouth. The larger the mouth, the larger the m’lo lugmav. Conversely, the smaller the mouth, the smaller the m’lo lugmav. For purposes of drinking on Yom Kippur we say an average adult has a m’lo lugmav that is larger than 1.5 fl. oz. (44 ml). A teenager may have a smaller m’lo lugmav. One can ascertain his or her personal m’lo lugmav by filling his mouth completely with water, expelling the water into a measuring cup and dividing the amount in half. This number is the amount held by one cheek - a m’lo lugmav. Pachos mi'keshiur is slightly less than this amount. This "test" should preferably be conducted before Yom Kippur. How infrequently should a person who is forced to drink on Yom Kippur take a drink so that his intake does not qualify for halachic drinking? Ideally, less than a m’lo lugmav may be consumed and then repeated up to every seven minutes. If this amount of liquid is insufficient for the patient, one may drink this amount of liquid every two minutes. Note: If it is determined that this amount is insufficient and one's life may still be in danger, the patient must drink as much as necessary, even if it is more than the shiur of volume and less than the shiur of time. On Yom Kippur, the pachos mi’keshiur amounts of food and drink are independent of each other. This means the two shiurim do not combine and one can simultaneously eat and drink a pachos mi’keshiur of both. The waiting times are also calculated independently. If one must eat on Yom Kippur, the following sample schedule of eating pachos mi’keshiur may be implemented: Eat and drink at 8:00 a.m., drink - 8:07, eat - 8:09, drink - 8:14, eat - 8:18, drink - 8:21, eat - 8:27, drink - 8:28, drink - 8:35, eat - 8:36, etc. This schedule is for someone who wishes to eat as much as possible pachos mi’keshiur in the shortest amount of time. Obviously, a choleh may eat and/or drink pachos mi’keshiur less frequently (e.g. eat and drink pachos mi’keshiur at 8:00 a.m., then eat and drink again pachos mi’keshiur at 8:15 a.m., etc.). If possible, the decision whether one may eat or must eat - pachos mi’keshiur or more than the shiur - should be discussed with a competent halachic authority before Yom Kippur. I hope this is of help to you – Blessings.