The Law Code of Yājñavalkya 1.5.29

1.5.29

pratyaham annaṃ pitṛbhyo manuṣyebhyaś ca yathāśakti deyam | annābhāve kandamūlaphalādi | tasyāpy abhāve jalaṃ deyaṃ apiśabdāt | svādhyāyaṃ satataṃ kuryād avismaraṇārtham | na paced annam ātmārtham | annagrahaṇaṃ sakalādīyadravyapradarśanārtham | kathaṃ tarhi | devatādyuddeśenaiva || 1.1.04 ||

Every day, food should be given according to one’s capacity to the ancestors and human beings. In the absence of food, tubers, roots, fruits, and the like [should be given]. In the absence of even that, water should be given, as indicated by the word “even” (api). One should constantly perform personal recitation to prevent forgetfulness. One should not cook food for one's own sake. The mention of “food” is meant to indicate all consumable substances. How then? Only by dedicating it to the deities and so forth.