Gymnosophists is the name given by the Greeks to certain ancient Indian philosophers who pursued asceticism to the point of regarding food and clothing as detrimental to purity of thought. They were noted to have been vegetarian by several Greek authors. There were also gymnosophists in Upper Egypt who were called Ethiopian Gymnosophists by Apollonius of Tyana.

Pythagoras of Samos was an ancient Ionian Greek philosopher, polymath and the eponymous founder of Pythagoreanism. His political and religious teachings were well known in Magna Graecia and influenced the philosophies of Plato, Aristotle, and, through them, the West in general. Knowledge of his life is clouded by legend; modern scholars disagree regarding Pythagoras's education and influences, but they do agree that, around 530 BC, he travelled to Croton in southern Italy, where he founded a school in which initiates were sworn to secrecy and lived a communal, ascetic lifestyle. This lifestyle entailed a number of dietary prohibitions, traditionally said to have included aspects of vegetarianism.