Chandogya Upanishad 5.16.2

5.16.2

atsy annaṃ paśyasi priyam \
atty annaṃ paśyati priyaṃ bhavaty asya brahmavarcasaṃ kule ya etam evam ātmānaṃ vaiśvānaram upāste \
(S ) tv eṣa ātmana iti hovāca \
(S ) te vyabhetsyad yan māṃ nāgamiṣya iti \\516.2\

‘So you eat food and see what is dear. One who thus meditates upon this Vaiśvānara Ātman, eats food and sees what is dear, and there is in his family the holy effulgence born of sacred wisdom. But this is only the lower belly of the Ātman. If you had not come to me your lower belly would have burst.’