The most observant Rastas follow a dietary law called ital, the name of which is derived from the word "vital."
Ital food is food which is completely natural (not canned and free of chemicals and preservatives) and eaten as raw as possible. Old Testament prohibitions against pork and shellfish are part of Ital, but most Rastafarians are vegatarians or vegans. Coffee and milk are also rejected as unnatural.
Rastafarians reject the excessive use of alcohol, since it is a fermented chemical that does not belong in the temple of the body and it makes a person stupid, thereby playing into the hands of white leaders. This is contrasted with the holy herb of marijuana, which is natural and believed by Rastas to open their mind and assist in reasoning.