For Orthodox Christians, there are four fasting seasons, which include Nativity, Great Lent, Apostles' Fast and Dormition. Fasting during these times refers to abstention from animal products, olive oil (or all oils, according to some Orthodox traditions), wine and spirits. However, shellfish is allowed in some traditions, though other kinds of meat are not. Fasting can take up a significant portion of the calendar year. The idea is not to suffer, but to use the experience to come closer to God, to realize one's excesses and for alms giving. Fasting without prayer and almsgiving (donating the money saved to a local charity, or directly to the poor, depending on circumstances) is considered useless or even spiritually harmful by many Orthodox Christians.

Those desiring to receive Holy Communion keep a total fast from all food and drink from midnight the night before.