The diet follows the principle of "two to five, four to four, and fresh".

Zhang Zhongjing had special requirements for his diet. It was not that he favored delicacies from the mountains and the sea or had chicken, duck, fish and meat at every meal, nor did it mean that he only had a preference for vegetarianism and no meat. Instead, it referred to the "two and five, four and fresh" he recorded in "Essential Prescriptions from the Golden Cabinet". What does "two and five, four plus freshness" mean? It refers to the staple food in the diet being a combination of grains and coarse and fine grains. The nature and flavor of the dishes in the side dishes should be in harmony with the taste of the cooking. The diet used should be combined with the characteristics of the four seasons' climate, and all food ingredients should be fresh. How exactly did Zhang Zhongjing do it? In spring: The staple food mainly consists of various kinds of noodles processed from wheat with a sweet and cool nature, and is accompanied by some rice porridge. The side dishes mainly consist of pungent and sweet foods, such as scallions, coriander, leeks, carrots, peanuts, Chinese cabbage, chicken, pork, etc. As the climate starts to milder in spring, the Yang energy in the human body begins to rise, and the metabolism within the body gradually becomes vigorous. Therefore, it is advisable to consume more pungent and sweet foods to boost the Yang energy and facilitate metabolism. At the same time, it is also advisable to consume sweet and cool staple foods to prevent excessive Yang energy, which may be detrimental to the body. In this season, it is advisable to avoid sour and astringent flavors as they can hinder the rising of Yang energy. In summer: The staple food is mainly millet with a sweet and cold nature, combined with noodles, and some mung beans are often added to thin porridge. The side dishes mainly consist of sweet, sour, and refreshing foods, including various green vegetables, tomatoes, winter melons, loofahs, as well as eggs, duck eggs, beef, etc. Due to the hot climate in summer, the Yang energy in the human body is abundant on the outside and the Yin energy is weak on the inside. Choosing products with a cold, cool, sweet and sour, and moistening nature can not only clear heat and dispel summer heat, but also the sweet and sour nature can transform Yin and protect Yin energy. During this season, it is advisable to avoid spicy foods to prevent further damage to the Yang energy. However, it is also feared that excessive consumption of sweet and cold foods can easily harm the Yang energy of the spleen and stomach, which is not conducive to digestion and absorption. Therefore, it is necessary to frequently use some garlic to prevent this drawback. In autumn: Both staple and side dishes should be sweet and moist. The staple food mainly consists of grains such as rice and glutinous rice, supplemented by some noodles and sweet potatoes. Sesame and walnut kernels are often added to thin porridge. In addition to using a variety of vegetables as side dishes, one should also consume more fruits. The meat products used include pork, rabbit meat, river fish, etc. As the climate in autumn is cool and dry, eating more sweet and moistening foods can promote the production of body fluids and relieve dryness. During this season, it is also necessary to avoid spicy food, especially raw scallions and chili peppers. In addition, it is necessary to use less bitter and cold, sweet and cold, and dispersive ingredients such as bitter gourd, cucumber, and coriander. The taste of the cooking should be light and refreshing. In winter: The staple foods are mainly sweet and warm in nature, such as noodles made from corn and sorghum, and are often combined with some rice and flour. In thin porridge, some kidney beans and red adzuki beans are often added. Vegetables with the functions of nourishing Yin, subduing Yang and regulating qi are commonly used as side dishes, such as Chinese cabbage, green radish, white radish, bean sprouts and black fungus. For meat products, choose those that are sweet and warm and can assist Yang, such as mutton, dog meat, and chicken. Due to the cold climate in winter, the Yang energy within the human body is latent. Using more foods that nourish Yin, subdue Yang and regulate qi can prevent the latent Yang energy from transforming into fire and harming the body's vital energy. At the same time, they also consume sweet and warm foods that boost Yang to enhance sexual function and resist cold. The food cooked in this season should have a combination of five flavors and be slightly stronger. It is forbidden to be picky or eat too much of a certain flavor of food. Zhang Zhongjing insisted that the raw materials of the food he drank must be fresh and clean. For instance, the grains must be produced in the current year and processed on the spot. If there were any moldy or insect-eaten grains, they would never be processed into rice or flour. Most vegetables should be freshly picked from the vegetable fields. Even if they are taken out of the vegetable cellar in winter, there should be no rotten ones or those that have lost too much water and withered. The meat should be freshly slaughtered without any diseases. If the internal organs of the slaughtered meat are abnormal, it should also be refused to be put into the pot. It is said that once, a servant of his family bought a piece of pig liver from the market. Zhang Zhongjing noticed that the color of the liver was a bit abnormal and asked the servant if he had seen the slaughtered pig with his own eyes. The servant told him that he had gone late today and all the pigs had been slaughtered long ago, so he didn't see it. But seeing that there were many people buying it, he picked a piece and bought it. When Zhang Zhongjing heard this, he ordered his servant to cover it with soil and said that the color of this pig liver was abnormal and it could not be used. The servant felt it was a pity to do so and said, "It's fine to feed the pigs." Zhang Zhongjing, however, replied, "Since this pig liver cannot be eaten by humans, it is also not suitable to feed it to pigs. Wouldn't it be even more regrettable if pigs got sick after eating it?" The servant had no choice but to bury the pig liver in the soil. From this small incident, it can be seen how strict Zhang Zhongjing was about the freshness of food ingredients. To sum up, some people might think that Zhang Zhongjing's requirement of "two to five, four to four, and freshness" for diet is a bit excessive and rigid. In fact, diet is closely related to human health. It serves as the nutritional foundation for essence, energy and spirit. The requirement for diet is to be reasonably balanced, comprehensively compatible and clean and hygienic, with the aim of preventing diseases from entering through the mouth or causing illness due to improper diet. Only by paying attention to diet and ensuring adequate nutrition sources can one enjoy good health and a long life. The reason why Zhang Zhongjing was particular about his daily diet lies precisely here. His views on diet are worth our reference, study and research.