In the first century, Jews fasted on Mondays and Thursdays. The original Christians were all Jewish and were used to the fasting as a spiritual discipline. They moved the fast days to Wednesdays and Fridays, because Judas engineered Jesus' arrest on a Wednesday and Jesus was crucified on a Friday. Most often that fast took the form of avoiding meat in the diet. In those days, meat was a luxury food. You either had to buy it in a market or you had to own enough land to keep cattle. On the other hand, anyone could grow vegetables or forage for them, and anyone could catch a fish in a lake or a stream. You could buy better fish and vegetables, but the point is that you could eat without money if you were poor. So meat was rich people's food and fish was poor people's food. That is why the most common form of fasting was to omit meat and eat fish. The Wednesday and Friday fasts were a universal Christian custom in ancient times. The Eastern Orthodox still observe these fasts. The Roman Catholic Church downplayed the Wednesday fast, but kept the Friday fast until quite recently. Anglicans and Protestants also observed these fasts. In the 18th century, a man could not be ordained a Methodist minister if he did not fast on Wednesdays and Fridays, with the reasoning that a person who could not rule his own belly could certainly not rule the church. Ripped off some website