The works of Ādi Śaṅkarācārya

Taittirīyopaniṣadbhāṣyam

Verse 31

अन्नं न निन्द्यात् ।तद्व्रतम् ।प्राणो वाअन्नम् ।शरीरमन्नादम् ।प्राणे शरीरं प्रतिष्ठितम् ।शरीरे प्राण प्रतिष्ठितः ।देतदन्नमन्ने प्रतिष्ठितम् ।स य एतदन्नमन्नेप्रतिष्ठितं वेद प्रतितिष्ठति ।अन्नवानन्ना-दो भवति ।महान् भवति ।प्रजया पशुभिर्ब्रह्मवर्चसेन ।महान् कीर्त्या ॥ १ ॥

In plain words

Furthermore, because food serves as the portal through which Brahman is realized, it must never be slighted—revere it as you would a teacher. This is the specific vow enjoined upon the knower of Brahman. Such instruction exalts food, for food deserves praise as a direct instrument in realizing the infinite. Breath is indeed food, because it dwells within the body. Whatever is contained within something else serves as food for it; and since breath resides within the body, breath is the food of the body.

Close to the Sanskrit

Moreover, because Brahman is known through food as a gateway, therefore food should not be disparaged, like a teacher. That is taught as the vow of this very knower of Brahman. The teaching of the vow is for the praise of food, and food is worthy of praise because it is a means of attaining Brahman. Breath indeed is food, because breath is included within the body. Whatever is established inside of whatever, that becomes food for it. And breath is established in the body, therefore breath is food for the body.