Revākhaṇḍa ascribed to the Vāyupurāṇa (RKV) 54.51

54.51

dinaikabhojanāḥ kecit kecit kandaphalāśanāḥ /
trirātrabhojanāḥ kecitparākavratino 'pare //

some eating once a day, some feeding on roots and fruits,
some eating once in three nights, others observing the parāka vow;