There is a common saying among the people: "You nourish what you eat." This phrase sounds simple, but it has been widely spread and has a profound influence, and at least the Chinese people have firmly believed in it from ancient times to the present day. However, to understand the meaning of this saying, it must be explained in two layers. Is there a scientific basis for "you nourish what you eat"?
The first layer is "what to eat."
"What to eat" is the choice of food, but this choice is not only to satisfy the desire of the palate, but also for the need of "health," that is, how to strengthen vitality, eliminate diseases, and prolong life. The Chinese have had a basic view of "eating" since ancient times: everything that can be eaten is a medicine. Common vegetables, fruits, grains, and poultry, when eaten, all have the effect of nourishing and treating the body. Therefore, at the beginning of civilization, food and medicine were not distinguished. Later, with the advent of medicine, food and medicine were divided into two categories, but the medicinal function of food was still widely valued. To some extent, the food therapy school of Chinese health preservation spends no less effort on the choice of food, that is, "what to eat," than on medicine. In the Song Dynasty, food formulas emerged, and health preservationists promoted their importance and necessity in this way:
The foundation of the body must depend on food. If one does not know the proper diet, one cannot survive. Distinguish the five meats, five fruits, and five vegetables, but first, the five grains. For the endless cycle of life, nothing is better than the five grains as the finest of seeds. If one understands this principle, one can pacify the organs, nourish the blood and qi, please the spirit and refresh the mind, and eliminate illnesses. Why seek from outside? The real Sun said that a doctor must first understand the source of the disease, know what has caused it, and treat it with food. If food therapy does not cure, then one can use medicine...
Examining the food therapy school, its source is long and continuous, with representative figures in each era. Far back, we can mention Yi Yin of the Shang Dynasty. Yi Yin's adoptive father was a chef of the Youxin clan. When Yi Yin grew up, he became an expert in cooking and had a deep understanding of the taste and effects of food. He once said to King Tang of Shang: "Use the new to replace the old, the pores will be unblocked, the vital energy will be renewed day by day, the evil qi will be completely eliminated, and the body will be unimpeded and not closed." His words can truly serve as a basic theoretical program for the food therapy school. Later generations revered him as a gourmet and a medical expert, which is not an exaggeration at all. In more recent times, we can mention Hui Sihui of the Yuan Dynasty, who wrote "Yinsheng Zhengyao"; Gao Lian of the mid-Ming Dynasty, who wrote "Zunsheng Bajian"; and Zhu Yizun of the early Qing Dynasty, who wrote "Shixian Hongmi." Hui Sihui was the great master of the food therapy school. He served as the Imperial Dietitian, in charge of the imperial court's diet and medicinal tonics, and was a senior nutritionist by the emperor's side. Hui Sihui, based on the eating and drinking practices of the imperial aristocracy, and referencing various "Bencao" (materia medica) works and the methods of famous doctors, summed up a complete set of food tonification and food therapy methods and theories, which he wrote into "Yinsheng Zhengyao." Its original purpose was to serve the emperor's "sacred life to reach infinity," but objectively it also became a practical guide for the application of food therapy in health preservation. Gao Lian was a polymath who lived among the common people. From his own long-term experience with illness, he put forward clear views and requirements on the structure of diet: "Guard against the hardship of rich and greasy food, and practice self-cultivation, even if it troubles the heart and abdomen." This requirement, when extended, basically fits the health preservation standards of the urban class. As for Zhu Yizun, he was a famous scholar of his time. Why did he develop such a great interest in food issues besides his studies of classics and history? Since the preface by the author of "Shixian Hongmi" is lost, we cannot know for sure. Perhaps Zhu Yizun did not consider "eating" to be a trivial matter. The Confucian classic "Liji" (Book of Rites) contains many records of cooking, and Confucius also said a long passage, "Do not be tired of refined rice, do not be tired of finely minced meat." Valuing the nourishment of life is not only a concept of Lao Zhuang Taoism, but Confucianism also takes it seriously. The three people above represent the common position held by the upper class, urban society, and intellectuals in China on the relationship between diet and "health." This seems to indicate that in the traditional Chinese way of life, "what to eat" had a widespread consciousness. Behind this consciousness is the worldly concern for life. Therefore, "those who cultivate life cannot fail to make their diet beautiful." People even pinned their hopes of longevity on diet and tonification, so that "what to eat" became the ideal goal for many people to live and live well.
The second layer is "you nourish what you eat."
Because the first layer of "what to eat" embodies the important goal of protecting life, "you nourish what you eat" is a purposeful method and strategy. The meaning of this phrase should first be reversed to be correct, that is, you eat what you need to nourish. According to the classic Chinese medical text "Huangdi Neijing" (The Yellow Emperor's Inner Canon), people in the "post-heaven" stage, due to environmental influences, their life is constantly being depleted day by day, making it difficult to live a long life. This depletion occurs in all parts of the body, but generally in two major aspects: depletion of yin and depletion of yang. Therefore, nourishment is needed—nourishing yin and nourishing yang. If nourished well, life can be extended, living to be 100, 200, 800, or even 1000 years old, and even becoming an immortal. The standard for "what to nourish" in later generations is determined by the words "yin" and "yang." Once "what to nourish" is determined, "what to eat" is relatively determined. However, "what to eat" has a very wide variety. According to the "Five Elements" and "Five Colors," and also considering the "Five Flavors," to replenish one deficiency in the body, there are many things that can be eaten. For example, if your spleen and stomach are weak, you can list dozens of porridges just to nourish the spleen and stomach, allowing you to eat endlessly. This is of course troublesome, but the Chinese people seem not to be afraid of trouble, and the result of the trouble is that it becomes increasingly worth "what to eat." In this way, a one-to-one corresponding relationship between the object of eating and the object of nourishment has developed. In other words, "eating A to nourish A" and "eating B to nourish B." Here, the "analogy theory" of classical Chinese medicine is undoubtedly applied more simply when selecting the objects for eating and nourishing, and "using the mind to prescribe medicine" is replaced by the food therapy school's "using the mind to choose food." If a person has a kidney deficiency, then it goes without saying that pig kidneys, sheep kidneys, dog kidneys, etc., are the best foods for him to nourish his kidneys. By analogy, any problems with the heart, lungs, spleen, stomach, liver, and other organs can be solved by this method of analogy, taking the corresponding parts from other animals to cook and eat, achieving the purpose of nourishment and treatment. What if a person has a congenital leakage of true qi? Naturally, he needs to replenish the deficiency by eating qi. There is a guiding method that will teach him to face southeast at midnight, inhaling and exhaling the heavenly gang qi. There is also another person who feels that his physical body is not strong and durable enough, and hopes that one day he will be as indestructible as metal. He would then need to ingest golden elixirs and eat stones as food. Or, to be simpler and more convenient, according to the recommendation of the late medical official Zhang Junyi: eat silk. Because silk threads are long, eating them will make one's life equally long, until becoming an immortal. When Su Dongpo learned of this wonderful method of eating silk, he joked that from then on, people would probably "eat clothes for meals." This kind of inversion of things不难想见 that in past times, people truly had a spirit of daring to think and daring to eat.
The health preservationists spared no effort in pushing "you nourish what you eat" to the extreme of immortal ingestion, revealing obvious absurdity. To some extent, this was limited to satisfying the immortality fantasies of scholars and gentry, which probably had little significance for the common people. The common people are after all different from the fanciful scholars and gentry; they do not necessarily seek to become immortals. Therefore, for the common people, the most desired realization of "you nourish what you eat" is very secular and very practical. To cater to the wishes of the common people, the most effective method for health preservationists is to implement it in "nourishing yin and strengthening yang." In modern times, the popular saying "you nourish what you eat" in the marketplace, its meaning and target are self-evident, and everyone understands it. Secular desires are very normal. Urban commoners and ordinary people also demand a strong body in their lives of "food, drink, and sex." Therefore, "wherever there is a well," one can hear talk of "three whips" and "five whips." Although unavoidably coarse, it is a long-standing tradition with deep meaning. The Chinese people's firm belief in "you nourish what you eat" is a point that must be mentioned.
When it comes to this, what I have to say is probably complete. What remains is that today "you nourish what you eat" is still a popular saying among the public. Although this phrase is often spoken by elegant people in high-class restaurants and banquets, it still carries the flavor of health preservationists from the past two thousand years.