From the dawn of Christianity, Friday has been signalized as a day of abstinence, in order to do homage to the memory of Christ suffering and dying on that day of the week. There has always been a clear distinction between fasting and abstinence. According to Church usage, fasting indicates a restriction of the quantity of food (currently, one large meal and two small meals) while abstinence indicates a restriction of the quality of food (today, no meat). There are indications to fasting and abstinence in the scriptures and writings of saints.
In the Old Testament
Fasting, implying abstinence, was ordained by law for the Day of Atonement (Leviticus 16:29). Besides this passage the scriptures contains many others which show how adversity moved the Jews to assume the burden of fasting and abstinence in a spirit of penance (cf. Judges 20:26; Judith 6:20; Joel 1:12; 2:15).
In the New Testament
In St. Matthew’s Gospel we see how Christ spent forty days in the desert, during which time he tasted neither food nor drink. No doubt Jesus’ action is to serve as an example for his followers (cf. Mt 4:1-11). The only piece of clearly defined legislation concerning abstinence embodied in the New Testament was framed by the Council of Jerusalem, prescribing “abstinence from things sacrificed to idols, and from blood, and from things strangled” (Acts 15:29). The Acts of the Apostles also gives evidence of a tendency on the part of the Church, as an organized body, to prepare the way for important events by abstinence and fasting (Acts 13:3; 14:23).
St. Paul sets forth the necessity of abstinence when he says that “everyone striving for self-mastery must abstain from so many things” (1Cor 9:25); and “let us be God’s servants working, watching, and fasting”, which he often practiced (2 Cor 6:4-5; 2Cor 11:27).
Church Laws on Abstinence
Under current Church law, the days of abstinence fall during Lent, the season of spiritual preparation for Easter. On Ash Wednesday and all of the Fridays of Lent, Catholics over the age of 14 are required to abstain from meat and from foods made with meat. The Church recommends abstinence on all Fridays of the year. You may abstain from meat or substitute it with some other form of penance.
The Church frames her laws of abstinence to meet the exigencies of fallen human nature. With the fall of human nature to Original sin, we incurred darkness in our understanding, weakness in our will, and turbulence in our passions. Your passions were given to you to satisfy the legitimate cravings of human nature and enable you develop your being according to the dictates of reason. But it is evident from experience that our passions could invade the domain of reason and usurp her sovereignty. In order to keep the passions under the control of reason, you have to enforce strict discipline; or else you are will soon become a slave to unbridled passion. This is what St. Paul means when he says: “The flesh lusts against the spirit, and the spirit against the flesh” (Galatians 5:17).
The Saints Have Something to Say
St. Thomas Aquinas says that “the flame of lust is doused by abstinence from food and drink.” Besides, abstinence exercises a salutary influence in leading man to supra-sensible pursuits. St. Augustine says that abstinence purifies the soul, elevates the mind, subordinates the flesh to the spirit, begets a humble and contrite heart, scatters the clouds of concupiscence, extinguishes the fire of lust, and enkindles the true light of chastity. This is summarized in the official message of the Church found in the Mass-preface used during Lent: “Who by bodily fasting suppresses vice, ennobles the mind, grants virtue and rewards.”
From our different sources, we see that abstinence is not only a religious observance. It is also a form of prayer and discipline. Focus on Jesus and on the cross when you abstain from meat. Your discipline should also lead you out of sin and toward God. They say absence makes the heart grow fonder. I guess you could say that abstinence makes the body (and soul) grow holier… if we embrace it and allow it.