By Tayiba Ahmed
Every year more than a billion Muslims from all around the world fast for a period of one month. This is the ninth month of the Islamic Calendar, the holy month of Ramadan. Fasting is one of the five pillars of Islam and Muslims fast for this one month duration daily from dawn till sunset. While Muslims in some countries have to fast for around nine hours, fasting time in some of northern hemisphere countries can last for more than 20 hours.