As recorded in Suwen (Plain Questions), chapter Zangqi Fashi Pian (Treatise on Regulating the Zang-Qi in Accordance with the Seasons): “Medicinal substances attack pathogenic factors; the five grains provide nourishment; the five fruits offer support; the five livestock supply benefit; and the five vegetables provide enrichment.” This passage indicates that the five grains constitute the primary source of daily sustenance and form the material foundation of life activities, whereas fruits, livestock, and vegetables contribute diverse nutrients, serving supplementary and harmonising roles. In other words, although medicinal substances may dispel pathogenic factors, a well-regulated and balanced diet is the fundamental basis for preserving healthy qi and nourishing the body.

A proper diet lies not only in the diversity of foods consumed, but also in their appropriate combination. The integration of whole grains and refined grains promotes more balanced nutrition. As stated in Lingshu (Spiritual Pivot), chapter Yingwei Shenghui Pian (On the Convergence of Nutritive and Defensive Qi): “Humans receive qi from the grains. The grains enter the stomach and are transmitted to the lungs; the five zang and six fu all receive qi from this.” If the intake of grains is insufficient, the qi and blood will be depleted. 

Furthermore, traditional Chinese medicine recognises that foods possess the five flavours, namely sour, sweet, bitter, pungent and salty, which correspond respectively to the liver, spleen, heart, lung, and kidney. As recorded in Suwen (Plain Questions), chapter Liujie Zangxiang Lun (Treatise on the Visceral Manifestations in Relation to the Six Periods): “The five flavours enter the mouth, are stored in the stomach and intestines … and thereby nourish the five qi.” Moderate and balanced use of the five flavours can nourish the zang-fu organs; however, habitual excess or partiality towards a single flavour may instead cause injury. The Huangdi Neijing (Yellow Emperor’s Inner Canon) further cautions: “When food and drink are taken in excess, the intestines and stomach are injured.” Thus, the art of dietary regulation lies in moderation, proportionality, and balance.