The fast of Tish’a beAb should be observed by all those who are in good health. There are some exceptions, as explained below, almost all related to health issues.
PREGNANT AND NURSING WOMEN
Similar to Yom Kippur, pregnant and nursing women should observe this fast. In cases of complicated pregnancies or physical weakness, or if the pregnant mother is worried that fasting will affect her health or her baby’s health, she should ask her doctor before the fast-day and proceed as the physician recommends. If during the fast a pregnant woman feels sick, especially if she is vomiting or having any signs of dehydration, she should break the fast and drink or eat immediately. However, mild dizziness and nausea that can be coped with by lying down on a couch or a bed are considered normal.
YOLEDET
During the first 30 days after birth or a miscarriage, a woman is exempted from fasting on the 9th of Ab.
CHOLE SHE-EN BO SAKANA
People with a chronic disease like diabetes or patients under treatment or someone with high fever or with any symptoms of dehydration should not observe the fast. In some cases, when is not possible to fast for 24 hours it would recommended to fast from dawn until the end of the day, as we do on the 17 of Tamuz or the 10 of Tebet.
ELDERLY
Elders should consult with their doctors to ensure that fasting will not affect their health. If fasting can affect their health, they are exempt from (or are forbidden to) fasting.
MINORS
In many Ashkenazi communities, children fast for a few hours during Tish’a beAb once they reach nine years of age , because is important to make them share the experience of national mourning. According to Rabbi Obadia Yosef, howsever, the Sephardic custom it is that children under 13 and girls under 12 are totally exempted from fasting. His reasoning is that, unlike Yom Kippur, there is no need for children to fast for a few hours because while fasting on Yom Kippur is part of the process of Teshuba (= repentance, improving our behavior), fasting on Tish’a beAb is done because we are mourning for the destruction of our Bet haMiqdash. And while we definitely want to educate and train our children to do Teshuba, many Sages understood that we are not required to train our children to mourn, before they have a formal obligation to do so (12 or 13 years old ,קטן פטור מאבלות). Hoping that B”H this will the last year we would cry for not having our Bet-haMiqdash, and that next year, mourning for the Bet haMiqdash will not be necessary.
HOW TO PROCEED WHEN YOU NEED TO EAT ON TISHA BEAB?
On Yom Kippur, when one is allowed to eat for health reasons, food should be eaten in small portions. Tish’a beAb is different, because unlike Yom Kippur, it is not a Biblical commemoration. Therefore, when one is allowed to eat during Tish’a beAb for health reasons, one can eat normally. However, when eating in Tish’a beAb, one should not eat delicious food or in excess, but only what is needed to feel well.