The Church enters into a unique liturgical period after the Mass of the Lord's Supper on Holy Thursday.
The Mass does not conclude with a final blessing, and instead ends on a quieter note with no official dismissal.
Instead, the Church invites the faithful to enter into Christ's Passion in a unique way. It is a somber period in the Church's liturgical calendar, one that is reflected by the way the liturgy is conducted.
One additional way to enter into Jesus' suffering that the Church provides for the faithful is the "Paschal Fast."
The Roman Missal even mentions this tradition, "The Paschal Fast should also be kept sacred. It is to be celebrated everywhere on the Friday of the Lord’s Passion and, where appropriate, prolonged also through Holy Saturday as a way of coming, with spirit uplifted, to the joys of the Lord’s resurrection."
Good Friday
The first part of this fast is the typical Good Friday fast that the Church already proscribes.
According to the USCCB, the following rules for fasting are in force for those between the ages of 18 and 59:
Fasting on these days means we can have only one full, meatless meal. Some food can be taken at the other regular meal times if necessary, but combined they should be less than a full meal. Liquids are allowed at any time, but no solid food should be consumed between meals.
Holy Saturday
The second part of this fast is optional and includes fasting on Holy Saturday.
For many centuries there was a strict fast on Holy Saturday, permitting no food to be eaten in observance of this painful day. Many would stay in the church throughout the day, keeping Jesus company in the tomb.
Not everyone can observe such a fast two days in a row, and so there exist no rules that are to be observed.
If you are interested in prolonging a fast into Holy Saturday, be sure to consult your doctor and spiritual director first, only committing to something that won't harm your physical or spiritual health.
Even if you don't engage in a strict fast on Holy Saturday, you can do something simple like not eating between meals or not eating meat.
Whatever you do, keep in mind the spirit behind these fasts, inviting you to prepare your heart for the joyous celebration of Easter.