In those churches which follow the Rite of Constantinople, i.e., the Eastern Orthodox and the Byzantine Rite Eastern Catholics (not all Eastern Catholics), the forty days of Lent and of fasting, which include Sundays, begin not on Ash Wednesday, but on Clean Monday. Lent then ends on the fortieth day from that date, which is the Friday before Palm Sunday. The days of Lazarus Saturday, Palm Sunday and Holy Week are considered a distinct period of fasting. For more detailed information about this practice of Lent, see the article Great Lent. In addition, determination of the date of Easter in the East is not based on the Gregorian calculations (see Computus). In most years this results in a difference of some weeks, which can be as many as five.
Among the Oriental Orthodox, there are various local traditions regarding Lent. The Coptic, Ethiopian and Eritrean Orthodox Tewahedo Churches observe eight weeks of Lent, which, with both Saturdays and Sunday mornings exempt, has forty days of fasting. Fast generally implies one meal a day to be taken either in the evening or after 2.45 p.m. with total abstention from meat, fats, eggs and dairy products. Instead they use cereals, vegetables and other type of food devoid of fats. Smoking is a breach of the fast, which runs for a total of 56 days.