China's understanding of food nutrition and its impact on human health has a long history. As early as more than 3,000 years ago, during the Western Zhou Dynasty in ancient China (about11year BC-77 1 year BC), the official medical system divided medicine into four categories: food doctors, disease doctors, choice 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. The classic Chinese medicine book Huangdi Neijing written from the Warring States Period to the Western Han Dynasty more than 2,000 years ago? In Su Wen, the principle of "five grains for nourishment, five fruits for help, five livestock for benefit, five vegetables for filling, and the combination of smells to supplement lean qi" was put forward, which was the earliest concept of dietary balance. The Elbow Backup Emergency Prescription written by Ge Hong in the Eastern Jin Dynasty records six methods to treat and prevent beriberi, such as douchi, soybean, adzuki bean, flax, milk and crucian carp. In the aspect of diet and health preservation, the Tang Dynasty medical scientist Simiao emphasized conforming to nature, especially avoiding the harm of "too much" and "insufficient". 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 food function is concerned, "using it to satisfy hunger is called food, and treating disease is called 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, Taiping Shenghuifang, written by Wang Huai Yin in the Song Dynasty, recorded dietotherapy methods for 28 diseases. In the Yuan Dynasty, Hu Sihui and others wrote "Drinking Diet", which made a deep study on various health foods, tonic medicinal diets and cooking methods. In the Ming Dynasty, Li Shizhen summarized the pharmaceutical experience of China before16th century and wrote Compendium of Materia Medica, in which there were 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 about nutrition and health care in traditional Chinese medicine, namely, the theory of homology of medicine and food, the theory of taste of food function, the theory of ascending, descending, floating and sinking of food, the theory of reinforcing and reducing food, the theory of meridian tropism of food and the theory of dialectical food application. Based on the theory of traditional Chinese medicine, these theories study the relationship between diet and health from the perspective of syndrome differentiation, synthesis, connection and development.

/kloc-Before the middle of the 8th century, although a large number of opinions, theories and even theories had been formed about the relationship between diet, nutrition and health, some of which were still verified in practice, most of these understandings were the accumulation of superficial perceptual experience, and they lacked a comprehensive and essential understanding of things (for example, they knew nothing about the composition of food and human body at that time). It was not until 1785 that the "chemical revolution" took place in France, and some major chemical elements were identified and some chemical analysis methods were established, 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 in 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 of biochemistry, microbiology, physiology and medicine.