The Fourth Precept You shall observe the days of fasting and abstinence established by the Church
The fourth precept ensures the times of ascesis and penance which prepares us for the liturgical feasts and helps us acquire mastery over our instincts and freedom of heart (CCC 2043)
In our instant gratification culture, fasting seems a very foreign concept. Yet fasting is very clearly taught by Jesus. In Matthew 6:16-18, Jesus tells His disciples, “When you fast…” and tells them not to be showy about it. And in Luke 9:23, Jesus says, “If anyone wishes to come after me, he must deny himself and take up his cross daily and follow me.” Fasting is simply part of the practice of self-denial about which Jesus spoke. As the catechism says, fasting “helps us acquire mastery over our instincts.”
For Catholics there are only two days each year were fasting is required: Ash Wednesday and Good Friday. All other Catholics between the ages of 18-59 are bound to observe the fast. On fast days, one full meatless meal may be taken, and two other smaller meatless meals, sufficient to maintain strength according to one’s needs. Abstinence from meat is to be observed by all Catholics over 14 years of age on Ash Wednesday and all the Fridays during lent, including Good Friday.
Finally, fasting and abstinence are meant to bring our hearts and minds closer to God. When we feel hose pangs of hunger, we turn to God in prayer and ask for the strength to carry on and are reminded of the hunger in our hearts which can only be filled by Christ.