I wrote two years ago on this matter.Fasting from the Eucharist isn’t something we’re required to do, although Cardinal Ratzinger did write about the practice; here is an excerpt from someone else’s
A problem that all of us are heir to is the possibility that we will allow the reception of Communion to become routine and, thus, fail to allow it to attain the transforming effect it is intended to bring about in our lives. Following up on what he had written about the plight of those deprived of Eucharist, Cardinal Ratzinger speaks, surprisingly but wisely, about
fasting from the Eucharist. {cf. Pilgrimage Fellowship, pgs. 86-88} He makes important cautionary points: if done, it
ought to be infrequent and for a limited time; it
should not be chosen without the advice and direction of a wise spiritual director who will help the one fasting to discover the motivation and clarify the purpose for such an action; and the goal should be to deepen one’s appreciation for the Eucharist so that it is received in the future with greater concentration and deeper love. The Cardinal points out that as fasting from physical food breaks what is normal and necessary for the sake of some spiritual gain, so
sacramental fasting is not normal and therefore only to be cautiously entered into.Pope Leo XIII wrote about the practice in passing in his encyclical
Mirae Caritatis (n. 19) of 1902:But the chief aim of our efforts must be that the
frequent reception of the Eucharist may be everywhere revived among Catholic peoples. For this is the lesson which is taught us by the example, already referred to, of the primitive Church, by the decrees of Councils, by the authority of the Fathers and of the holy men in all ages. For the soul, like the body, needs frequent nourishment; and the holy Eucharist provides that food which is best adapted to the support of its life. Accordingly
all hostile prejudices, those vain fears to which so many yield, and their specious excuses from abstaining from the Eucharist, must be resolutely put aside; for there is question here of a gift than which none other can be more serviceable to the faithful people, either for the redeeming of time from the tyranny of anxious cares concerning perishable things, or for the renewal of the Christian spirit and perseverance therein. To this end the exhortations and example of all those who occupy a prominent position will powerfully contribute, but most especially the resourceful and diligent zeal of the clergy. For priests, to whom Christ our Redeemer entrusted the office of consecrating and dispensing the mystery of His Body and Blood, can assuredly make no better return for the honor which has been conferred upon them, than by promoting with all their might the glory of his Eucharist, and by inviting and drawing the hearts of men to the health-giving springs of this great Sacrament and Sacrifice, seconding hereby the longings of His most Sacred Heart.This was followed by
Sacra Tridentia of 1905, which explained some of the history of the practices of receiving Communion (ir)regularly, and promoted regular reception.