What is required from us on days like today (Good Friday) in terms of fasting and abstinence?

From the Catechism of the Catholic Church: (“You shall observe the prescribed days of fasting and abstinence.”) ensures the times of ascesis and penance which prepare us for the liturgical feasts; they help us acquire mastery over our instincts and freedom of heart.

Church Law on Fasting and Abstinence

Fasting is listed as a precept of the Church: “You shall observe the days of fasting and abstinence established by the Church” (CCC 2043). This means that Catholics are under grave obligation to substantially observe these laws. Christians are required by divine law to do penance for their sins, penance is not optional.

The Church, as a caring mother, is providing us a specific means and season for completing acts of penance. Her goal is to see to it that her children attain eternal life. Her precept on fasting, then, is for our spiritual benefit. Catholics who intentionally neglect and/or reject all forms of penance violate divine law and thus would be guilty of grave sin. Grave sin committed with full knowledge and full consent is by definition mortal sin and thus places a soul in peril (CCC 1857).

Because the season of Lent is of penitential character, the Church sets forth the days of penance as Ash Wednesday and all Fridays during Lent. Catholics are obliged to both fast and abstain from flesh meat on Ash Wednesday and Friday of the Lord’s Passion and abstain from flesh meat on all other Fridays during Lent. These requirements are binding on Catholics of the following age ranges:

Latin Rite Catholics from age 18 up through to the beginning of their 60th year (their 59th birthday) are required to fast, unless they have a serious reason for not doing so. According to Pope Paul VI’s apostolic constitution Paenitemini, “The law of fasting allows only one full meal a day, but does not prohibit taking some food in the morning and evening, observing, as far as quantity and quality are concerned approved local custom.” (Paenitemini, ch. III., III., 2).

It’s often thought that a person can have one full meal and two “lesser meals” that cannot add up to a full meal. But Paenitemini doesn’t require us to weigh up food to make sure it doesn’t equate to a full meal. The point is, only one full meal is allowed, and one can take some food two other times on that day. Liquids such as juice, coffee, tea, or milk do not technically violate the fast, although refraining from ingesting any animal products such as milk is virtuous.