'And he who offers the fourth oblation, should offer it to Samâna (on-breathing), saying Svâhâ. Then Samâna is satisfied,

In plain words: The teaching treats eating as a sacred fire offering. The fourth bite of food is offered to Samana, the breath that digests food and spreads it through the body, with the word "Svaha" (a call said when making an offering). Then that breath is satisfied.