The first prominent modern vegetarian was the Greek philosopher Pythagoras who lived towards the end of the 6th century BC. The Pythagorean diet came to mean an avoidance of the flesh of slaughtered animals. Pythagorean ethics first became a philosophical morality between 490-430 BC with a desire to create a universal and absolute law including injunctions not to kill “living creatures,” to abstain from “harsh-sounding bloodshed,” in particular animal sacrifice, and “never to eat meat.”
The diet followed Pythagoras was lacto vegetarian, ie eat: Fruits, vegetables, cereals, nuts, legumes and dairy minimally, in order from the largest to the smallest amount. Said that one should not eat the factors together with the output (eg chicken and egg) and avoid almost all generally seafood. Cereals were the basis of the diet of the Golden Age of people like Hesiod tells us in his “Works and Days” and the staple food of the Pythagoreans. “For lunch the Pythagoreans used only bread (with yeast) and honey” (Iamblichus, “On Long Pythagoras”, par 97).