XXVI

The discipline of fasting before communion has a long history, as Pope Pius XII states in his 1953 apostolic constitution, "Christus Dominus":

"From the very earliest time the custom was observed of administering the Eucharist to the faithful who were fasting.

Abstinence from food and drink is in accord with that supreme reverence we owe to the supreme majesty of Jesus Christ when we are going to receive Him hidden under the veils of the Eucharist. And moreover, when we receive His precious Body and Blood before we take any food, we show clearly that this is the first and loftiest nourishment by which our soul is fed and its holiness increased. Hence St. Augustine gives this warning: 'It has pleased the Holy Ghost that, to honor so great a Sacrament, the Lord's Body should enter the mouth of the Christian before other food.'

Before the time of Pius XII the Eucharistic fast was from midnight onward and included water. This also meant that Masses were only celebrated in the morning.

Pius XII mentions some of the difficulties preventing many from receiving Communion. Among them are the shortage of clergy, especially in mission lands, and the pace of modern life in factories and offices which include night shifts. He also desired to open up the possibility of celebrating Mass in the evening on important feasts so that more people could attend.

Thus, among other things he established that water and medicine would no longer break the fast. He also mitigated the fast under certain circumstances. In 1957, with the document "Sacram Communionem," he changed the law again, to require only a three-hour fast.

Pope Paul VI brought in the present discipline in November 1964, and this forms the basis of Canon No. 919.

Canon 919
1. One who is to receive the Most Holy Eucharist is to abstain from any food or drink, with the exception only of water and medicine, for at least the period of one hour before Holy Communion.
2. A priest who celebrates the Most Holy Eucharist two or three times on the same day may take something before the second or third celebration even if the period of one hour does not intervene.
3. Those who are advanced in age or who suffer from any infirmity, as well as those who take care of them, can receive the Most Holy Eucharist even if they have taken something during the previous hour.

How many times per day can one receive Holy Communion?

One of the significant changes for the faithful in the Code of Canon Law which was promulgated in 1983 was the permission to receive Holy Communion more than once per day. In the past the law set certain conditions, such as participation in a funeral, marriage or ordination Mass. The new canon, however, simply states,

c.917 A person who has received the Most Holy Eucharist may receive it again on the same day only during the celebration of the Eucharist in which the person participates. 

920 §1. "After being initiated into the Most Holy Eucharist, each of the faithful is obliged to receive holy communion at least once a year."

920 §2. "This precept must be fulfilled during the Easter season unless it is fulfilled for a just cause at another time during the year."

In the past, people spent a lot of time in mortal sin, or at least in a state unworthy to receive the Eucharist. Therefore for someone to receive it was a major life event. This kind of culture was undone by Pope St. Pius X at the turn of the 20th Century.

(One probable reason why the Church prescribed the law to receive communion at least once a year may have been that due to long fast the faithful may have been unprepared for receiving communion most of the days of the year.)

Frequent Communion increases our love for God and for our neighbor, which expresses itself in action, which makes us more like Christ.

Venial sins are forgiven when we receive the holy communion with proper repentance.

Physically, frequent Communion relieves us of our passions. Priests and other spiritual directors who counsel those who are struggling with passions, especially sexual sins, often urge frequent reception not only of the Sacrament of Confession but of the Sacrament of Holy Communion. By receiving Christ's Body and Blood, our own bodies are sanctified, and we grow in our likeness to Christ. In fact, as Fr. John Hardon points out in his Modern Catholic Dictionary, the Church teaches that "A final effect of Communion is to remove the personal guilt of venial sins, and the temporal punishment [earthly and purgatorial] due to forgiven sins, whether venial or mortal."