Each organ has an affinity to certain foods. If an organ system is weak, one can eat more of the foods that stimulate that organ thus increasing its energy. At a very basic level we see that the Liver attenuates to sour, the Heart to bitter, the Spleen to sweet, the Lung to pungent and the Kidney to salty.
Each food is categorized according to its flavor, its inherent temperature effect on the body, whether it causes energy to rise or fall in the body and several other categorizations. You can see with all this information, one could create a very specific diet that could treat disease. That’s exactly how the Chinese Medicinal Diet evolved.