Kashrut
Among the numerous laws that form "kashrut" are prohibitions on the consumption of certain animals (such as pork and shellfish), mixtures of meat and milk, and the commandment to slaughter mammals and birds according to a process known as "shechita". There are also laws regarding agricultural produce that might impact the suitability of food for consumption.
Vegetarianism and religion
Within Eastern Christianity, Vegetarianism is practiced as part of fasting during the Great Lent (although shellfish and other non-vertebrate products are generally considered acceptable during some periods of this time); vegan fasting is particularly common in Eastern Orthodoxy and Oriental Orthodox Churches, such as the Coptic Orthodox Church of Alexandria, which generally fasts 210 days out of the year.