The Official Website of Grand Ayatollah Makarem Shirazi

Even though fasting is one of the main branches of religion and it has been emphasized a lot in narrations, it becomes haram on some occasions, which are as follows. 1. fasting on Eid al-For and Eid al-Aḍḥā 2. The fast of a woman when it is in conflict with the conjugal rites of her husband and he does not give consent to it. Even if it is not in conflict with her husband's rite, the obligatory precaution demands that she obtain his permission before fasting. 3. The recommended fast of children is not permissible if it causes inconvenience for their parents. However, children are not required to obtain their parents' permission for fasting. 4. The fast of one who is certain that fasting will do them harm. In this situation, if one fasts, it is invalid and they have to perform the qada of the fast later. Even if one thought that fasting was not harmful for them but after iftar they realized that it was, it is recommended for them to perform the qada of the fast. 5. One who deems it highly probable that fasting will be harmful for them, whether they deem it probable themselves or a trustworthy physician has diagnosed so. 6. Fasting on the Yawm al-shak, meaning the day about which one is doubtful whether it is the last day of Shaban or the first day of Ramadan, with the intention of it being the first day of Ramadan, unless one observes that day's fast with the intention of fasting for the month of Shaban. Fasting is not permissible for six groups of people, but it is still recommended for them to abstain from things that invalidate fasting. 1. Travelers who have broken their fast on a journey and have arrived in their hometown or in the place where they intend to stay for 10 days before noontime. 2. Travelers who have arrived in their hometown or in the place where they intend to stay for 10 days in the afternoon. 3. A sick person who has recovered from their illness before noon but have done things that invalidate fasting. 4. A sick person who has recovered from their illness in the afternoon even if they have not committed any of the fast invalidators. 5. A woman who has become pure in the middle of the day from menstruation or bleeding after childbirth. 6. Non-Muslims who have converted to Islam on a Ramadan afternoon, but if they have converted to Islam before the noontime without having committed any of the fast invalidators based on obligatory precaution.