The types of food allowed to the Orthodox faithful during the religious fast days, especially during the Great Lent (Η Μεγάλη Σαρακοστή or Η Μεγάλη Τεσσαρακοστή) before Easter.
The Orthodox church uses the revised Julian calendar (rather than the Gregorian calendar used by most Western churches) to establish the date of Easter each year, so the dates rarely coincide. Only Greek Easter is never before Latin Easter; it's usually one or two weeks after.
During fast days, the faithful refrain from eating the flesh of red-blooded animals and their products (eggs, milk, cheese etc), and fish and seafood with backbones (ie. shellfish, but prawns and octopus are fine). There are also restrictions on the use of yeast, olive oil and wine. Those who follow Lent strictly substitute vegetable oil and margarine for olive oil. Often permitted dishes tagged on dishes in restaurants during the period so the faithful known what to order.
In practice, many Greeks only seriously fast on the holiest days, Clean Monday (Καθαρά Δευτέρα when every bakery sells lagana) and on Good Friday.
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