All creation has a body and a soul. The food we eat has vitality. Food has the energy of G-d. This energy or speech of G-d becomes impregnated in all creation. When we(I) eat food, we are not only ingesting the physical elements of food we are also ingesting the spiritual elements of the food.
The Torah wants us to know that not only is there a physical experience when we(I) eat food there is also a spiritual experience associated with the food we ingest. Thus the soul of the food nourishes the soul of the person.