Many people are aware that a good diet is essential for wellbeing. In China where dietary guidelines follow nature this has been practised for centuries.
In Traditional Chinese Medicine, eating seasonal foods may be seen as a way to build up energy and prepare for the coming seasons. 
The ancient Chinese may have commonly eaten foods that were in season in the belief that it would help them build up energy reserves and prepare for seasonal changes. The theory is that yang qi tends to flow outwards and occupies the body surface in spring and summer and therefore, the innards get relatively depleted of yang qi and need replenishing. At the same time, the weather in autumn and winter is cold and dry, and many TCM practitioners believe it is important to keep warm and prevent dryness during the season through the methods of replenishing yin and nourishing dryness,
According to TCM philosophy, if we consume seasonal foods, we may remain in harmony with the natural environment. Different foods are seen to have different yin and yang qualities. The basic principles include nourishing yang in spring and summer, and nourishing yin in autumn and winter.