The ancients kept in good health five things: keeping in good health has nothing to rely on, and its advantages are: washing feet every night, taking a thousand steps after meals, eating a bowl of white rice at dawn, not ordering food, and giving injections regularly. It is said that if you sit still, Jize's spleen will not digest. Three or four of these five things can be done, which is better than taking medicine. ([Qing] Zeng Guofan: "The Complete Works of Zeng Guofan, Letters from Home" On the evening of August 25th of the decade of Tongzhi, "Ji Hong Yu Jize")