Fasting, as far as Islamic Shari`ah is concerned, is not meant for torturing people and overburdening them. Rather, it is meant for their physical and spiritual health.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states, Fasting, we may do well to recall, is prescribed by Allah, our Creator, for our own physical and spiritual health; it is in no way intended to cause us hardship or torture. Therefore, while we are ordered to fast if we are physically of sound health, we are not at all advised to do so if it is found to be detrimental to our health.
Therefore, if you have been advised by your family physician not to fast because of your medical condition, then you are best advised not to fast, especially if it has been determined to be detrimental to your health. Allah says in the Qur’an, {As for those who are sick or traveling, they should skip fasts (during Ramadan), while making up for the days missed later when they get better. If some are unable to make up (because of old age or incurable medical conditions), they should offer fidyah (compensation) to feed a poor person (for each day of fasts they have thus missed)) (Al-Baqarah 2:184).
So, I advise you to forego fasting and pay the fidya. In our Canadian situation, it is estimated to be equivalent of seven Canadian dollars; you may give this amount directly to the poor or entrust the same to reputable charities to distribute it to the poor locally or overseas; you may also send it to your country of origin, if you think that there are people with greater need for assistance.