Regulations for Fasting and Abstinence

Abstinence: Catholics from age 14 are obliged to abstain from meat on Ash Wednesday, Good Friday, and all Fridays during Lent.
Fasting: Catholics ages 18-59 are obliged to fast from food on Ash Wednesday and Good Friday. The fast requires that a person eat the equivalent of less-than-two meals in place of the typical three meals eaten during a day.

Taken from “Fast and Abstinence” from the USCCB.