Who decided that Orthodox fasting must include abstaining from animal products?
This form of fasting was passed on in the early Church from Jewish practice. In Matthew, Christ says, “When you fast do not be like the hypocrites,” which indicates that the Jews fasted — it also indicates that Christ assumes that one fasts, for He says “when you fast” not “if you fast.” Fasting is not something that only developed alongside Christianity; rather, it is a practice that had been followed by the Jews, and even Scripture mentions that Christ fasted. Courtesy www.oca.org and Further Q&A on the Orthodox Faith by Fr.