The so-called fasting is to express piety. I don't eat for a month in Ramadan.

Keeping fit without eating is called crossing the valley.

"Pigu" originated from "not eating grains" in Taoist health preservation, and it was a common way of health preservation in ancient times. It originated in the pre-Qin period and was popular in the Tang Dynasty. Also known as "Valley Valley", "Valley Valley Valley", "Valley Valley", "Valley Valley" and "Hugh Valley". The earliest record of Bigu originated from Zhuangzi Xiaoyao Tour: "The mountain shot by the ancients is inhabited by immortals. If the skin is ice and snow, it is like a virgin, not eating grains, sucking wind and drinking dew, traveling around the world by flying dragons ... "As a way to prolong life, it is also recorded in many ancient books.