Xinzhai, rooted in the teachings of Daoist philosophy, encompasses the pursuit of inner purity and tranquility. The term "zhai" signifies the cleansing of desires and achieving a state of calmness within the mind. Its origins can be traced back to the "Zhuangzi," specifically the passage in the "Human World" section that states, "Only the Dao gathers emptiness, and emptiness is Xinzhai of the heart." This implies that the highest level of spiritual cultivation involves having a clear and tranquil inner state. Thus, practitioners of Daoism strive to cultivate a serene and pure heart, aligning themselves with the ultimate goal of spiritual growth.

In the Daoist context, Xinzhai goes beyond mere adherence to a vegetarian diet, although practitioners may choose to consume meat. Instead, it emphasizes the cleanliness and purity within one's heart and mind. This principle lies at the core of Daoist health practices, emphasizing the importance of nurturing the mind as a fundamental step toward nurturing the body.