Ahara suddhau sattva-suddhih

     Sattva-suddhau dhruva smrtih

     smrti-lambhe sarva-granthinam vipra-moksah

From purity of food comes purity of mind,

from purity of mind comes constant remembrance of God, and

from constant remembrance of God one becomes free from all bondage – one becomes liberated.

Reference:

Chandogya Upanishad

http://www.eng.vedanta.ru/library/gokulananda/purification_of_body_and_mind.php