Mbh 13.106.4d

He who passes one whole year observing fasts for three days in succession and taking food on every fourth day, and abstaining from injury from every kind, adheres to truthfulness of speech and keeps his senses under control, attains to the merit of the Vajapeya sacrifice. Such a person ascends to heaven after death and receives high honours there. That man, O son of Kunti, who passes a whole year observing fasts for five days and taking food on only the sixth day, acquires the merit of the Horse-sacrifice. The chariot he rides is drawn by Chakravakas. Such a man enjoys every kind of happiness in heaven for full forty thousand years. He who passes a whole year observing fasts for seven days and taking food on only every eighth day, acquires the merit of the Gavamaya sacrifice. The chariot he rides is drawn by swans and cranes. Such a person enjoys all kinds of happiness in Heaven for fifty thousand years. He who passes a whole year, O king, eating only at intervals of a fortnight, acquires the merit of a continuous fast for six months. This has been said by the illustrious Angiras himself. Such a man dwells in heaven for sixty thousand years. He is roused every morning from his bed by the sweet notes of Vinas and Vallakis and flutes, O king. He who passes a whole year, drinking only a little water at the expiration of every month, acquires, O monarch, the merit of the Viswajit sacrifice. Such a man rides a chariot drawn by lions and tigers. He dwells in heaven for seventy thousand years in the enjoyment of every kind of happiness. No fast for more than a month, O chief of men, has been ordained. Even this, O son of Pritha, is the ordinance in respect of fasts that has been declared by sages conversant with duties. That man who, unafflicted by disease and free from every malady, observes a fast, verily acquires, at every step the merits that attach to Sacrifices. Such a man ascends to Heaven on a car drawn by swans.