CHĀNDOGYA UPANISHAD · 7.9.1

अन्नं वाव बलाद् भूयः ।
तस्माद् यद्य् अपि दश रात्रीर् नाश्नीयात् ।
यद्य् उ ह जीवेत् ।
अथवाद्रष्टाश्रोतामन्ताबोद्धाकर्ताविज्ञाता भवति ।
अथान्नस्याये द्रष्टा भवति श्रोता भवति मन्ता भवति बोद्धा भवति कर्ता भवति विज्ञाता भवति ।
अन्नम् उपास्स्वेति ॥

annaṃ vāva balād bhūyaḥ ।
tasmād yady api daśa rātrīr nāśnīyāt ।
yady u ha jīvet ।
athavādraṣṭāśrotāmantāboddhākartāvijñātā bhavati ।
athānnasyāye draṣṭā bhavati śrotā bhavati mantā bhavati boddhā bhavati kartā bhavati vijñātā bhavati ।
annam upāssveti ॥

'Food (anna) is better than power. Therefore if a man abstain from food for ten days, though he live, he would be unable to see, hear, perceive, think, act, and understand. But when he obtains food, he is able to see, hear, perceive, think, act, and understand. Meditate on food.

F. Max Müller · The Upanishads, Sacred Books of the East 1 (1879)