As a food, congee can be savory or sweet, with meat or vegetables, and can be thick or thin. However, for health preservation, based on the experience of Daoists, Buddhists, health experts, and imperial physicians, it is most suitable to eat plain congee on an empty stomach in the morning.
Cao Tingdong, a famous health preservationist from the Qing Dynasty, suffered from many illnesses in his youth and never left his hometown. He immersed himself in the village's mountains and waters, cultivating his character and studying diligently. He became a master of literature, art, and poetry, and his works were frequently included in the *Siku Quanshu*. Cao Tingdong's ability to live to be over ninety in the medical environment of his time has become a legendary tale of health preservation. Cao Tingdong also combined the health wisdom of the ancients with his own practical experience to write "Essays on Health Preservation," which he titled *Lao Lao Heng Yan*. "Lao Lao" means "caring for the elderly," and the book is a treasure trove for enjoying a healthy and long life. In the "Morning Routines" chapter of this book, Cao Tingdong said: "Every day, on an empty stomach, eat a bowl of plain congee. It can promote the removal of old and the introduction of new, generate fluids, and please the stomach. The benefits are not small. If mixed with sweet or salty things, it is no different from an ordinary meal." This clearly explains that if plain congee is mixed with other ingredients, it becomes just a common food.
During the Tang Dynasty, the medical scientist Sun Simiao, who suffered from many illnesses in his youth and thus studied medicine, also advocated for eating plain congee in the morning. He used the wisdom of Buddhism and Daoism for health preservation and lived to be over a hundred years old. Additionally, he would cook medicinal herbs into congee, using the "energy of the rice" and the water as a "guide for the medicine." He would then use this to regulate the body and treat diseases according to the "biological clocks" of the five organ systems (Zang-Fu).
In ancient times, there were no refrigerators, so congee was cooked and eaten while still slightly warm. Nowadays, when used to satisfy hunger, congee that is cooked and left over can be stored in the refrigerator and then reheated with other ingredients when needed; there is no harm in this. However, as a morning congee for health preservation, freshly cooked congee is more beneficial to the body's vital energy.