Why Catholics Fast and Abstain
Every Lent, something strange happens in Catholic neighborhoods.
Fast food restaurants start advertising fish sandwiches.
Churches host fish fries.
And Catholic kids everywhere ask:
“Why is fish not meat?”
(Good question. We’ll get there.)
Wait… Isn’t Fasting Just an Old Testament Rule?
A lot of Christians think:
“Fasting and food rules were part of the Old Law. Jesus set us free. Christians don’t need rules about meat on Fridays.”
And at first that sounds right.
Jesus did declare all foods clean (Mark 7:19).
Christians are not bound by Jewish food laws.
But then you read what Jesus said about fasting, and you have to stop for a second.
Jesus Said “When,” Not “If”
In the Sermon on the Mount, Jesus says:
“And when you fast, be not as the hypocrites, sad. For they disfigure their faces, that they may appear unto men to fast. Amen I say to you, they have received their reward.”
— Matthew 6:16
When you fast.
Not if.
Jesus assumed His followers would fast.
He just wanted them to do it for God, not for show.
“Then They Shall Fast”
When people asked why Jesus’ disciples didn’t fast, He answered:
“Can the children of the bridegroom mourn, as long as the bridegroom is with them? But the days will come, when the bridegroom shall be taken away from them, and then they shall fast.”
— Matthew 9:15
Jesus told us exactly when His disciples would fast.
After He was taken away.
That is now.
Jesus Fasted
Jesus Himself fasted forty days in the desert before beginning His ministry (Matthew 4:2).
That is where the forty days of Lent come from.
And the early Church fasted before big decisions.
Before sending out Paul and Barnabas, the church at Antioch fasted and prayed (Acts 13:2–3).
When they ordained priests, they prayed with fasting (Acts 14:22).
Then You Read the First Christians
The Didache, a Christian manual from the late first century, says Christians should fast on Wednesdays and Fridays.
Why Friday?
Because Jesus died on a Friday.
Every Friday became a little Good Friday.
Christians have marked it with sacrifice ever since.
What Do Catholics Actually Do?
Here are the basic rules for Catholics in the United States today:
Fasting (one full meal and two small meals, nothing in between) on Ash Wednesday and Good Friday, for ages 18 to 59.
Abstaining from meat on Ash Wednesday, Good Friday, and all Fridays of Lent, for ages 14 and up.
On other Fridays of the year, Catholics are asked to do some act of penance; giving up meat is the traditional one.
Anyone who is sick, pregnant, or has health needs is excused.
So Why Is Fish Allowed?
In the old understanding, “meat” meant the flesh of warm-blooded animals, the food of feasts and celebrations.
Fish was the ordinary food of poor people.
Giving up meat meant giving up the feast and eating simply.
(If your Friday fish is lobster, you may have missed the point.)
Why Fast at All?
Fasting is not about earning God’s favor.
It is not a diet.
It is training.
When we say no to something good, like food, we get stronger at saying no to something bad, like sin.
Fasting makes room for prayer.
And the money and food we save can go to the poor.
Prayer, fasting, and almsgiving: the three things Jesus talks about together in Matthew 6.
So What Is the Catholic Claim?
Here it is in simple terms.
Jesus said “when you fast,” and said His disciples would fast after He was taken away.
Jesus fasted forty days, and the early Church fasted before important decisions.
The first Christians fasted on Wednesdays and Fridays.
Catholics fast and abstain to unite themselves with Christ’s sacrifice, grow in self-control, and make room for God and the poor (CCC 1434, 2043).
So the real question is not:
“Why do Catholics have rules about food?”
The better question is:
“If Jesus said His followers would fast, why did so many Christians stop?”
Because a little hunger can make a lot of room for God.
Keep reading: Why Catholics Go to Mass on Sunday, or browse more questions in Catholicism Explained.
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Catholic Sources
Scripture (Douay-Rheims): Joel 2:12; Jonas 3:5–10; Matthew 4:1–2; Matthew 6:1–18; Matthew 9:14–15; Acts 13:2–3; Acts 14:22.
Catechism of the Catholic Church: CCC 538–540 (Jesus in the desert); CCC 1434–1438 (penance and fasting); CCC 2043 (precepts of the Church).
Early Christian writers: The Didache 8 (late first century).
Church documents: Code of Canon Law, canons 1249–1253; Pope St. Paul VI, Paenitemini (1966).
