Great Lent is the longest and strictest fasting season of the year.
Week before Lent ("Cheesefare Week"): Meat and other animal products are prohibited, but eggs and dairy products are permitted, even on Wednesday and Friday.
First Week of Lent: Only two full meals are eaten during the first five days, on Wednesday and Friday after the Presanctified Liturgy. Nothing is eaten from Monday morning until Wednesday evening, the longest time without food in the Church year. (Few laymen keep these rules in their fullness). For the Wednesday and Friday meals, as for all weekdays in Lent, meat and animal products, fish, dairy products, wine and oil are avoided. On Saturday of the first week, the usual rule for Lenten Saturdays begins (see below).
Weekdays in the Second through Sixth Weeks: The strict fasting rule is kept every day: avoidance of meat, meat products, fish, eggs, dairy, wine and oil.
Saturdays and Sundays in the Second through Sixth Weeks: Wine and oil are permitted; otherwise the strict fasting rule is kept.
Holy Week: The Thursday evening meal is ideally the last meal taken until Pascha. At this meal, wine and oil are permitted. The Fast of Great and Holy Friday is the strictest fast day of the year: even those who have not kept a strict Lenten fast are strongly urged not to eat on this day. After St. Basil's Liturgy on Holy Saturday, a little wine and fruit may be taken for sustenance. The fast is sometimes broken on Saturday night after Resurrection Matins, or, at the latest, after the Divine Liturgy on Pascha.
Wine and oil are permitted on several feast days if they fall on a weekday during Lent. Consult your parish calendar. On Annunciation and Palm Sunday, fish is also permitted.