Shatapatha Brahmana 7.5.1.16

7.5.1.16

yadvevolūkhalamusale upadadhāti | prajāpatervisrastātprāṇo madhyata udacikramiṣattamannenāgṛhṇāttasmātprāṇo 'nnena gṛhīto yo hyevānnamatti sa prāṇiti

And, again, why he places a mortar and pestle thereon. From Pragâpati, when relaxed, the breath wanted to go out from within. He kept it back by means of food: hence the breath is kept back by food, for he who eats food, breathes.