The diet in spring should be based on the principle of gentle nourishment, with a focus on nourishing the liver and spleen. During this season, the liver governs the body's physiological functions, whose nature is akin to the sprouting of trees in spring, primarily responsible for the rise of yang energy throughout the body. If liver function is impaired, it disrupts the circulation of qi and blood, causing other organs to be affected and leading to disease. Furthermore, sour flavors enter the liver, which is its natural taste. If the already overactive liver in spring consumes excessive sour flavors, it will cause an excess of liver qi. Since the liver over-controls the spleen, this will inevitably damage the spleen. The spleen is also closely related to the stomach; therefore, a weak spleen hinders the digestive and absorptive functions of the stomach and spleen. Sweet flavors enter the spleen and are best for replenishing spleen qi. A healthy spleen, in turn, supports liver qi. Therefore, as the centenarian Tang dynasty physician Sun Simiao said, "reduce sour and increase sweet to nourish the spleen." This means eating less sour and more sweet foods to nourish both the liver and spleen, which is greatly beneficial for preventing disease and maintaining health.
Warm-natured and sweet-flavored foods are best, starting with grains such as glutinous rice, black rice, sorghum, millet, and oats; vegetables and fruits such as sword beans, pumpkin, lentils, red dates, longans, walnuts, and chestnuts; and meat and fish such as beef, pork tripe, crucian carp, crucian, sea bass, grass carp, and rice eel. By drawing rich nutrients from these foods, the effects of nourishing the liver and strengthening the spleen can complement each other.
Secondly, one should follow the ascending energy of spring and eat more foods that warmly tonify yang energy. Especially in early spring, when the lingering cold of winter remains, one can choose to eat chives, garlic, onions, konjac, turnip, mustard greens, cilantro, ginger, and scallions. These vegetables are all warm-natured and pungent in flavor, and can both dispel wind-cold and inhibit bacteria that breed in humid environments.
Again, on warm spring days or during sudden summer-like heat in late spring, it can easily stir up stagnant heat within the body, leading to liver fire, or cause the body's fluids to be lost. One can appropriately pair foods that clear internal heat and nourish the liver, such as buckwheat, Job's tears, shepherd's purse, spinach, water spinach, celery, chrysanthemum seedlings, lettuce, eggplant, water chestnut, cucumber, and mushrooms. These foods are all cool-natured and sweet in flavor, and can clear internal heat, moisten the liver, and improve vision.
As for fresh fruits, although they have the effect of clearing heat, generating fluids, and quenching thirst, most are sour and not suitable for excessive consumption in spring. If there is a need to clear internal heat, it is better to eat sweet and cool fruits like bananas, raw pears, sugarcane, or dried fruits like persimmon cakes.