The principle of diet in spring is gentle nourishment, with a focus on nourishing the liver and spleen. During this season, the liver is dominant, and its physiological characteristics are like the growth of trees in spring, governing the rise of yang energy throughout the body. If liver function is impaired, it leads to disorder in the circulation of qi and blood throughout the body, disturbing other organs and causing disease. Furthermore, the sour flavor enters the liver, which is its natural taste. If an already overactive liver in spring consumes an excessive amount of sour food, it will cause an excess of liver qi. Since the liver overacts on the spleen, this will inevitably damage the spleen. The spleen is also closely related to the stomach; thus, a weak spleen hinders the digestive and absorptive functions of the stomach and spleen. The sweet flavor enters the spleen and is best for replenishing spleen qi. A healthy spleen, in turn, assists liver qi. Therefore, spring nourishment should be as the centenarian Tang dynasty physician Sun Simiao said: "Reduce sourness and increase sweetness 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.
For foods that are warm in nature and sweet in flavor, the first choices are grains, such as glutinous rice, black rice, sorghum, broomcorn millet, and oats; fruits and vegetables, such as sword bean, pumpkin, lentil, red date, longan, walnut, and chestnut; and meat and fish, such as beef, pork tripe, crucian carp, crucian, sea bass, grass carp, and rice eel. By absorbing 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 qi. This is especially true in early spring when there is still the lingering cold of winter. You can choose to eat leeks, garlic, onions, konjac, turnip, mustard greens, cilantro, ginger, and scallions. These vegetables are all warm in nature and pungent in flavor; they can both expel wind and cold, and inhibit bacteria that breed in damp environments.
Again, on warm spring days or during the sudden heat of late spring, it is easy to stir up stagnant heat within the body, leading to liver fire, or cause the body's fluids to be lost. You can appropriately eat some 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 in nature and sweet in flavor, and can clear internal heat, moisten the liver, and brighten the eyes.
As for fresh fruits, although they have the effects of clearing heat, generating fluids, and quenching thirst, most are sour and not suitable for excessive consumption in spring. If you 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.