The Law Code of Yājñavalkya 1.2.76

1.2.76

brahmacarye sthita ekānnaṃ nādyād anāpadi vyādhyādyabhāve | brāhmaṇaḥ punaḥ śrāddhe 'bhyarthitaḥ san kāmam aśnīyāt | vratam apīḍayan madhumāṃsaparihāreṇa | atra brāhmaṇagrahaṇaṃ kṣatriyādeḥ śrāddhabhojanavyudāsārtham,

Established in studenthood, he should not eat food from a single person except in distress, [that is,] in the absence of illness and the like. A Brahmin, however, when invited to an ancestral rite, may eat at will, without impairing his vow, through the avoidance of honey and meat. Here, the mention of "a Brahmin" is for the purpose of excluding the Kshatriya and others from eating at an ancestral rite,