All life appears to be made of opposite yet complementary aspects: dark and light, cold and hot, receptive and creative, female and male, and so forth. Yang is the primary mover, the productive, the expansive while Yin is recessive, the cooperative, the sustaining. When Yang moves, Yin becomes apparent, as these two energies cannot exist separately.
This principle of energy applies to the external world as well as inside our bodies. In Chinese medicine, Yin and Yang are often referred to as the body's water and fire. Applying these principles to the body, we can determine whether a person is a Yin, or cold type or a Yang, or hot type.
We can also determine the energetic properties of foods, whether they are cooling or warming. To maintain balance, a cold type person needs relatively more Yang, or warming foods, and a hot type person needs relatively more Yin, or cooling foods. Yin and Yang also apply to the organs of the body based on whether they are solid (Yin) or hollow (Yang). Given the opportunity to heal, the body rebalances itself. Traditional Chinese Medicine assists the body in healing but does not interfere with the healing process.
The Western Nutrition model is the food pyramid, which to a practitioner of Chinese Medicine is cookie-cutter, inaccurate and imbalanced. The focus on Western Medicine is all in the science of food. There are classification systems such as calories, proteins, carbohydrates and fats that nutrition is summed up to. The difference is that this approach is not balanced for the body, especially a body that has ailments.