Shi liao is an abbreviation for shiwu liaofa (food therapy or diet therapy). Chinese diet therapy is a precious culture of Chinese nation, which is both ancient but also a newly developing science. Ancient people said “people treat food as heaven” which means food is an essential thing for human life. In order for humans to survive and be healthy they need to seek out and recognize comestibles, and discover the effect of food in maintaining health and preventing illness. Chinese diet therapy has a distant origin and a long history of five thousand years. It still enjoys broad popular acceptance among the general public. “Drugs and food share a common origin” and “Medicine and food share a common origin” are well-known folk sayings.

Chinese diet therapy is not just simply based on experience but part of the Chinese medicinal treasury. Therefore, the understanding of food properties and functions are built on traditional Chinese medicine theory. Because “drugs and food share a common origin,” Chinese medicine believes the property of food is the same as the property of drugs, which includes nature and taste, entering the channels, tonifying and draining, and other theories. The function of food is determined by the properties. The properties of food include “the nature of food,” “the qi of food,” and “the taste of food.” The function of food is the efficacy and action of the food. The properties of food are determined by the “four qi and five flavors.” The function of food on the human body can be generally divided into the three large categorizes of prevention, nourishment, and treatment.

Food is an essential material basis for activities of human life. A reasonable diet is a guarantee for health. On the other hand, improper diet will easily cause illness, and diet is an important measure for health care. In order for food to function as health care, we must observe the dietary health care regimen that considers different constitutions, age, gender, geography, season, and time.

The compatibility of food refers to the selective matching of two or more types of food. When they are mixed in the proper proportions, one can enhance the effectiveness of food and its edibility; but if they are not mixed in the proper proportions, there will be a deleterious effect. It is worth noting that Chinese diet therapy advocates dietary taboos, which include two concepts, generalized and narrow. The generalized dietary taboo needs to take into account differences in physique, age, gender, locality, season, time, and other various aspects, combined with the four qi, five flavors, food effects, and other theories to determine the taboos governing food compatibility. Diet taboo in a more narrow sense means “food to be avoided while sick.” In addition, there is the fawu taboo, which refers to food that can cause an old illness to relapse and a new illness to become more severe.

In order to have a healthy effect of health preservation from diet therapy, one also needs to have good eating habits. Good eating habits include nutritional balance, diet segmentation, hygiene care, health care during eating, and health preservation after meals.

Urbanization brings crowded living conditions, high-rise buildings everywhere, traffic congestion, information explosion, an accelerated pace of work and life, interpersonal tensions which easily cause a number of urban diseases such as “chronic fatigue syndrome,” cardiovascular disease, liver and gallbladder disease, gastrointestinal disease, skin eczema, cancer, and others. Under the guidance of Chinese medical theory, Chinese dietary therapy has adjunctive therapeutic and preventive recuperative functions in treating modern urban diseases.

From ancient to modern times, along with the propagation of Chinese culture, Chinese diet therapy has had a huge global influence, especially in such countries as Japan, Korea, and Singapore, which were influenced by Chinese diet health preservation culture from very early times. In the last several decades, Chinese diet therapy has become more widely accepted in Europe and America. As Eastern and Western cultural exchange has continued to expand and deepen, the wonderful blossom of Chinese diet therapy will fully bloom around the world.