The History of Lent
You may have wondered what the eating and fasting rules are for Lent and how things have evolved. According to the Catholic Education Resource Center the rules have varied. First, some areas of the Church abstained from all forms of meat and animal products, while others made exceptions for food like fish. For example, Pope St. Gregory (d. 604), writing to St. Augustine of Canterbury, issued the following rule: “We abstain from flesh, meat, and from all things that come from flesh, as milk, cheese and eggs.”
Since then, the guidelines have evolved and changed, while people are still encouraged to give up something for Lent as a sacrifice.