The basis of keeping in good health in the four seasons is to understand the atmospheric movement of the four seasons. For example, spring is the season when the sun's yang produces hair, and the qi of the human body also moves with the movement of the atmosphere, which is manifested in the birth and hair in the body. Hair growth is an upward and outward manifestation. According to Neijing, in spring, we should not suppress the qi of hair growth in the body. Acidic food has astringent effect. If you eat it when there is no discomfort in the human body, it will hinder the growth of liver qi, but it is not good for your health. However, due to the abnormal weather in spring, it is easy to produce too much hair (manifested by sudden overheating or strong wind). At this time, the yang of the human body will also produce too much hair, which is prone to symptoms such as headache, dizziness, sweating, cough and fever in the limbs. Eating some sour food can make liver qi return to normal and play a role in health care and treatment.

It is actually more difficult to truly understand the way of keeping in good health. The ancients said, "yin and yang are the basis of law, and numbers are the basis of art". Yin and yang are the yin and yang of heaven and earth, so we must first understand the characteristics of each season and even the solar terms before we can adjust our diet according to the solar terms. It is necessary to analyze the specific situation and not generalize it.