If one has a heter to eat shiurim on Yom Kippur these are the guidelines:
• Eating and drinking are two separate halachos. If one is allowed to drink doesn’t mean they’re allowed to eat and vice versa.
• Most of the time, drinking suffices.
• The shiur for drinking is one cheekful of liquid. (before Yom Kippur, fill up one cheek with liquid and spit it out. A little less than that is the shiur).
• If this is too difficult, then the measurement is 1 oz. of liquid.
• The shiur for eating is slightly more than 1 oz. (an average shot glass).
• One should start out eating and/or drinking every 9 minutes (from the end of the eating/ drinking until the beginning of the next eating/ drinking).
• If that’s not enough, move down to eating/ drinking every 4 and a half minutes.
• If that’s not enough, keep moving down until 2 minutes.
• If one has a heter to eat and drink then one of each can be consumed every 9 minutes etc. (one food and one drink. They don’t combine).
• If one is drinking because of precaution then it should be water. If one is drinking because they are sick then drinks with the most calories possible should be used.
• If one has a heter to eat and drink but by drinking something with high calories they can avoid eating, that’s what should be done.
• As long as a food is pourable then it has the status of liquid and not food. For example, smoothies are considered liquids.
• If one starts eating/drinking and then realizes that they don’t need anymore, they must stop.
• If by staying home one won’t have to eat/drink as much then they are required to stay home. You must stay home even if you’ll end up drinking just one less oz.
• One Bracha rishona is made at the beginning of eating/drinking and another Bracha isn’t made unless one decided to stop eating/drinking and then starts again.
• No bracha achrona is said.
