A person who follows vegetarianism — someone who avoids eating meat (and often fish), though inclusion of dairy or eggs varies by type.
彼は大学生のときから菜食主義者になった。
He became a vegetarian when he was at university.
旅行先のレストランに菜食主義者向けのメニューがあるか確認した。
I checked whether the restaurant at our destination had a menu for vegetarians.
菜食主義者でも、たんぱく質や鉄分の摂取に気をつける必要がある。
Even vegetarians need to pay attention to getting enough protein and iron.