China's understanding of food nutrition and its influence on human health has a long history. As early as 3000 years ago in the Western Zhou Dynasty (about11year BC-77 1 year BC), the official medical system divided medicine into four categories: food doctors, sick doctors, selected doctors and veterinarians, among which food doctors ranked first among the "four doctors". A food doctor is a doctor who specializes in diet and nutrition. Huangdi Neijing, a classic Chinese medicine book written by the Warring States to the Western Han Dynasty more than two thousand years ago? In Su Wen, the principle of "five grains for nourishment, five fruits for help, five livestock for benefit, five vegetables for supplement, and the combination of smells to supplement essence" was put forward, which was the earliest concept of dietary balance. Gehong in the Eastern Jin Dynasty recorded six methods to treat and prevent beriberi, including douchi, soybean, adzuki bean, flax, milk and crucian carp. In the aspect of diet health, the Tang Dynasty medical scientist Simiao emphasized conforming to nature, especially avoiding the harm of "excess" and "deficiency". In addition, he clearly put forward the concept of "dietotherapy" and the view that medicine and food are homologous, and thought that as far as the function of food is concerned, "those who use it to satisfy hunger call it food, and those who cure diseases call it medicine". In 659 AD, Meng E, a disciple of Sun Simiao, wrote the first monograph on dietotherapy, Dietotherapy Materia Medica. During the Song, Jin and Yuan Dynasties, dietotherapy and its application developed in an all-round way. For example, Wang Huaiyin's Taiping Sheng Huifang in Song Dynasty recorded the dietotherapy methods for 28 diseases. In the Yuan Dynasty, Hu Sihui and others wrote Drinking Diet, which made an in-depth study on various health foods, nourishing medicated diets and cooking methods. In Ming Dynasty, Li Shizhen summarized the pharmaceutical experience of China before16th century and wrote Compendium of Materia Medica, which contains 253 kinds of anti-aging health-care drugs and medicated diets.

In the historical process of exploring the relationship between diet and health for millions of years, human beings have not only accumulated rich practical experience and perceptual knowledge, but also gradually formed a unique theoretical system of nutrition and health care in traditional Chinese medicine, namely, the theory of homology of medicine and food, the theory of functional taste of food, the theory of ups and downs of food, the theory of food tonic, the theory of food meridian tropism and the theory of dialectical food application. These theories are based on the theory of traditional Chinese medicine, and study the relationship between diet and health from the perspectives of syndrome differentiation, synthesis, connection and development.

/kloc-Before the mid-8th century, although a large number of opinions, theories and even theories about the relationship between diet, nutrition and health had been formed, some of which were still verified in practice, most of these understandings were superficial accumulation of perceptual experience, and they lacked a comprehensive and essential understanding of things (such as knowing nothing about the composition of food and the human body at that time). It was not until 1785 that France's "chemical revolution" determined some main chemical elements and established some chemical analysis methods that the research of modern nutrition began (marking the beginning of modern nutrition), that is, those ancient or new nutritional viewpoints were systematically studied and verified at a deeper level by quantitative and scientific methods. Of course, the rapid development of nutrition in this period not only benefited from the rapid development of chemistry and physics, but also depended on the breakthrough achievements in biochemistry, microbiology, physiology and medicine.