What chemical interaction tricks the brain into sensing heat when consuming chili peppers?

Capsaicin binding to pain receptors in the mouth.

The sensation of heat experienced when eating chili peppers is not due to actual thermal energy but rather a chemical deception orchestrated by the compound capsaicin. This bioactive compound physically binds to specific pain receptors located in the tissues of the mouth. This binding action triggers a neurological response that mimics the signal normally sent when tissue is being burned, thereby tricking the brain into perceiving intense heat. This mechanism is crucial because it is this very interaction with pain receptors that underlies many of the scientifically interesting health effects associated with these fruits, even though the initial sensation is one of discomfort.