Bhagavad Gita 15.14

अहं वैश्वानरो भूत्वा प्राणिनां देहमाश्रितः।प्राणापानसमायुक्तः पचाम्यन्नं चतुर्विधम्॥

ahaṃ vaiśvānaro bhūtvā prāṇināṃ dehamāśritaḥ |prāṇāpānasamāyuktaḥ pacāmyannaṃ caturvidham ||

Having become the fire Vaisvanara, I abide in the bodies of living beings and, associated with the Prana and the Apana, digest the fourfold food.

Becoming the fire of life, I pass into their bodies and, uniting with the vital streams of Prāṇa and Apāna, I digest the various kinds of food.

Our plain-language meaning of this verse is waiting for scholar review.