Lent is the greatest and most solemn period of fasting on the Christian church’s calendar, leading up to the celebration of Christianity’s most important feast day: Easter.

Like most practices rooted in Christianity, the way people observe Lent, or whether they observe it at all, varies wildly depending on their heritage, specific religious tradition, and preferences. Still, there are some rules and guidelines that mark the observance of Lent for Christians who observe the season. And, increasingly, even nonreligious people are picking up the ritual.

• Western Christianity typically allows observers to pick whatever they want to fast from, based on a person’s understanding of what earthly comforts distract them from worship.
• Protestants in particular tend to avoid specific church-mandated practices when it comes to fasts.
• S...