Fasting in Orthodox Christian world is a way to clean up souls by willingly avoiding temptations of gluttony taste related to meat and other animal products as well as daily food quantities, throughout the fasting period. At the same time, people must keep away from “spiritual temptations” (passions,) too.
During the first millennia A.D. the Greek Orthodox Church defined the small and great fasting periods that Orthodox Christians should observe, in accordance with the fasting that our Lord Jesus Christ did for 40 day in the desert. Nonetheless, the fasting period “habits” of Orthodox Church found fertile “ground” within Greeks, since the ancient Greek dietary habits (e.g. Eleusinian mysteries – a ritual initiation) were very similar to the newly introduced rules. The catharsis of the body and mind is the target of any religion (Vedas, Bible, Koran) imposing fasting periods.