Q.| If someone is told by his physician that he should not fast, but partially disregarding his physician’s instructions, he fasts every other day, is he obligated to observe compensational fasting for those days he heeded his physician’s instruction and did not fast?
A.| If the physician instructing one to refrain from fasting is pious and trustworthy, and thus his word leads one to believe or, at least, fear that fasting is detrimental to one’s health, not only is it no longer obligatory to fast, it is rather impermissible to fast. If one recovers from the illness that had made fasting harmful prior to the arrival of the next month of Ramadan, one is obligated to observe compensational fasting (ṣawm al-qaḍāʼ) for the days of the month of Ramadan that one was affected with the illness, even those days that one fasted, for the fasting was not valid. If, however, the illness persists till the next month of Ramadan, one is absolved from the obligation to observe compensational fasting, one’s only obligation being to pay the canonically designated amount of financial expiation (fidyah) for every day one was prohibited from fasting due to illness, which is 750 grams of such food items as wheat, rice, or flour.