Ramadhan Fasting in the West

If Ramadhan begins tomorrow in Ontario, Canada, there will be almost 18 hours of fasting- no food or water.

The Quran was revealed in Mecca and Medina where fajr (dawn) and maghrib (sunset) did not extend for as many hours as they do in the West. Hence,  it is generally accepted that if a Muslim was to be living in the North Pole, he or she would not have to fast until sunset as that may not occur for months!!!

I am thinking of fasting according to the times of Mecca, Saudi Arabia, the place of the revelation of the Quran. I am not sure that fasting for almost 18 hours a day is healthy or advisable or that it was even intended by Allah.

What do you think about this? What do your schools of Islamic thought have to say about this?