Uttarajjhayana 16.8

16.8

no paṇīyaṃ āhāraṃ āhārittā havai, se niggaṃthe|
taṃ kahamiti ce?
āyariyāha–niggaṃthassa khalu paṇīyaṃ pāṇabhoyaṇaṃ āhāremāṇassa baṃbhayārissa baṃbhacere saṃkā vā, kaṃkhā vā, vitigicchā vā samuppajjijjā, bheyaṃ vā labhejjā, ummāyaṃ vā pāuṇijjā, dīhakāliyaṃ vā rogāyaṃkaṃ havejjā, kevalipannattāo vā dhammāo bhaṃsejjā|
tamhā khalu no niggaṃthe paṇīyaṃ āhāraṃ āhārejjā|

A Nirgrantha does not consume rich food.
Why is that?
The ācārya says: If a Nirgrantha practicing celibacy consumes rich drink and food, there may arise in his celibacy doubt, longing, or uncertainty, or he may suffer a breach, or incur madness, or contract a long-lasting and painful illness, or fall away from the Dharma taught by the omniscient ones.
Therefore, indeed, a Nirgrantha should not consume rich food.