The Talmud points to the relationship between the soul and the body as a model for the nature of G-d’s relationship with the world. The soul cannot be perceived by the senses, yet its presence and effect is keenly felt in every part of the body; so too, G-d, though He transcends our reality and is utterly beyond its perception, vitalizes the entirety of creation and is fully present in its every nook and cranny. Food is the glue that keeps soul and body together, sustaining the embodiment of the spirit within its material shell.
Diet is fundamental in a holistic approach to good physical and emotional health. The Rebbe points out that Kosher food encourages good health of the body and the mind, and spiritual health of the soul.