The application of medicated diet food, like therapy and drug therapy, also has its basic laws. These basic principles are the experience accumulated in the long-term medical dietotherapy health care and treatment, and the rules summarized from these practical experiences form the dietotherapy rules. However, when applying these specific rules, it should also vary from time to time, from place to place and from person to person, and it is not possible to copy them mechanically, otherwise it will be counterproductive. The following will introduce the common principles of dietotherapy: (1) Treatment based on syndrome differentiation, and food and gas must be congenial: this is the most basic principle of dietotherapy in China. Traditional Chinese medicine treats all kinds of food as medicine, and each food has sexual taste, meridian tropism and different functions. Therefore, when choosing food, we should first understand the symptoms of patients or the physical attributes of normal people, so as to determine the food to eat, treat diseases or regulate physical fitness in a targeted manner, and achieve the purpose of curing diseases and maintaining human health. Traditional Chinese medicine believes that the "secret of yin and yang" of normal people is the harmony of qi and blood, yin and yang, and normal diet and daily life. Some people have no obvious symptoms, but in some ways, there are signs of imbalance between yin and yang. Physiologically, there are obvious differences between cold body and hot body. If you are hot, you should eat cold food, such as mung beans, spinach, cucumbers, watermelons, lotus seeds, tremella, ducks, river fish, turtles and so on. And eat less hot and dry things. If you are afraid of cold, you should eat more warm food, such as onion, leek, ginger, garlic, longan, mango, pumpkin, beef, eel, marine fish, chicken, quail, etc., and eat less cold food.

(2) Carry out the principle of "five flavors are harmonious, and the nature and taste are superior": five flavors are abstract concepts of the role of traditional Chinese medicine in medicine and food, which are generally "pungent, pungent, sour, sweet, bitter, firm, salty and soft". The same taste has similar effects, but different tastes have different effects. Harmony of five flavors means that we must pay attention to the opposition and coordination between foods with different tastes, such as turtle and amaranth, chicken and eel, honey and onion, etc. Because of the disharmony in nature and taste, there are generally different usages. Another meaning of "harmony of five flavors" is that when using different flavors of food, the proportion between them should be appropriate. For example, "cereal, meat, fruits, vegetables" and other foods should be eaten together, so that the composition of the diet can be extensive and perfect. The dispute between sex and taste refers to the targeted use of "sex and taste dispute" food to correct the decline of yin and yang after understanding the current situation of imbalance between yin and yang in human body. "Five flavors are combined, and the nature and taste are superior to each other" is the law that dietotherapy must follow, and it is the method of correct treatment, that is, the general law that concretely implements the therapeutic principles such as "warming meridians to dispel cold, warming meridians to dissipate heat, tonifying deficiency and purging excess".

(3) Food is expensive and frugal, food is not miscellaneous, and the stomach is willing to make up: the quantity and quality of food cannot be increased or decreased at will during diet therapy. "Diet should be moderate, and the harmony of five flavors has always been emphasized in Neijing. In the process of dietotherapy, we should first find out the patient's situation and make a judgment, and then make a targeted diet plan. Food must be reasonable and of appropriate quality. After the prescription of medicinal diet and dietotherapy is issued, it must be carefully implemented. In practice, it is necessary to observe the patient's reaction to food treatment. The food used by patients must be comfortable and free from adverse reactions. If they have abdominal distension, abdominal pain, nausea and vomiting, they must find out the reasons and adjust their diet until the patients feel comfortable and have no adverse reactions after eating. " Stomach happiness can be digested and absorbed, which plays a beneficial role in human body. It is also necessary to prevent excessive fasting or fasting for too long, otherwise it will bring adverse consequences to patients.