Happy Pancake Day 2018!
In the past the ideas was for families to clear out their cupboards and remove the fattening foods (normally the tempting ones) so they aren't in their house during Lent.
Eggs, milk and sugar aren't traditionally eaten in fasting season, so need to be scoffed beforehand.
The actual tradition of mixing them up for pancakes is thought to come from a pagan ritual, but others say it is a Christian tradition - with each ingredient representing one of the four pillars of the faith. Eggs for creation, flour sustenance or the staff of life, salt for wholesomeness and milk for purity. Link