Bṛhadāraṇyaka Upaniṣad 1.3.17

Then breath (vital), by singing, obtained for himself eatable food. For whatever food is eaten, is eaten by breath alone, and in it breath rests. The Devas said: `Verily, thus far, whatever food there is, thou hast by singing acquired it for thyself. Now therefore give us a share in that food.' He said: `You there, enter into me.' They said Yes, and entered all into him. Therefore whatever food is eaten by breath, by it the other senses are satisfied.