Life of Saint Irene https://orthochristian.com/96000.html
Why do we fast on Wednesdays and Fridays?
Wednesday is the day on which Judas went to the leaders of the Jews and agreed to betray our Savior. Friday is the day on which Our Lord suffered His terrible Passion on the Cross. In repentance for our sins, and to honor His sufferings for us, the Church dedicates many of the hymns of nearly every Wednesday and Friday throughout the year to the Cross of Christ, and we fast on these days nearly every week. This is explained in the Synaxarion read at the Nymphios Service on the night before Holy Wednesday every year, the night on which we remember the betrayal of Judas and the repentance of the sinful woman who washed Our Lord’s feet with precious ointment, her hair, and her tears.
The Rules of Fasting
According to the Holy Canons and Sacred Customs of the Orthodox Church, as Passed Down from the Holy Apostles and Our Holy Fathers of the Earliest Generations of the Church
Wednesdays and Fridays – We fast on every Wednesday and Friday throughout the year except during the following periods:
Fasting Seasons – During these holy seasons, every day is a fast day:
Special Fasting Days - We always fast on:
How Strictly Do We Fast on Certain Days?
The basic fasting “diet” excludes meat, dairy products, fish, alcohol, and foods cooked in oil. This is called “xerophagia,” that is, “dry eating.” Most Wednesdays and Fridays, as well as all the weekdays of Great Lent and the 15 in August, are supposed to be days of “xerophagia.”
On Saturdays and Sundays during the fasts, we are always allowed at least oil and wine, except on Holy Saturday, which is a day of xerophagia. On Saturdays and Sundays on which we are preparing for Holy Communion, we eat only a little oil.
On the Saturdays and Sundays of the Apostles’ Fast, we eat fish, as well as oil and wine.
The same holds true for the Nativity Fast, until St. Spyridon’s Day (12/25 December), when we stop eating fish.
On the Tuesdays and Thursdays of the Apostles’ Fast and Nativity Fast, we have oil and wine.
The Beheading of the Forerunner (29 August/11 September) and the Exaltation of the Cross (14/27 September) are always days of xerophagia, except when they fall on Saturday or Sunday, when we have oil and wine.
Fasting in Preparation for Holy Communion
Those who normally keep the established fasts should keep xerophagia for three days before receiving Holy Communion.
Those who are lax in keeping the fasts the rest of the year must fast for at least 8 days of xerophagia before receiving Holy Communion.
If a Saturday or Sunday falls during our keeping of xerophagia before Communion, we should eat a little bit of oil on these days, to honor their joyful character in the spirit of the canons which forbid strict fasting on these days.
Everyone should consult his spiritual father regarding how strictly one should fast. This is ESPECIALLY true in the case of small children, those who are ill or elderly, and pregnant women. The above rules are practical guidelines and must be applied with discretion!