Bhagavad Gita, Chapter 17, Verse 7

The food also which is liked by each of them is threefold, as also Yajna, austerity and almsgiving. Do you hear this, their distinction.

Something as ordinary as food preference is named here as a real, visible clue to someone's deeper nature.

Krishna draws a direct line from what someone eats to which mode actually governs them. Real, everyday choices are shown reflecting something much larger.