ואתה קח לך מכל מאכל אשר יאכל…(נח ו:כא)

The Ramban explains that permission to eat the flesh of animals was granted in Noach’s time, after the flood, because Noach had sustained them in the teivah (the Ark). As a reward for caring for them, Hashem allowed Noach and his descendants to eat meat.

The phrase “ואתה קח לך” — “and you, take for yourself” — contains the word “קח” (take), which connotes “קנין” (acquisition), as seen in קידושין ב. By bringing the animals into the teivah, Noach in a sense “acquired” them — creating a new kinyan, a new right — through which he was now permitted to eat meat.