Yamasmriti 10

10

ekaikaṃ varddhayec chukle kṛṣṇapakṣe ca hrāsayet /
amāvāsyāṃ na bhuñjīta eṣa cāndrāyaṇo vidhiḥ //

One should increase [the food] by one [morsel] during the bright fortnight, and decrease it during the dark fortnight, / and should not eat on the new-moon day; this is the cāndrāyaṇa rule.