Pancakes are eaten on this day as Lent is a period of fasting, during which only the plainest foodstuffs may be eaten. Therefore traditionally, rich ingredients such as eggs, milk, sugar and flour are eaten immediately prior to the commencement of the fast and pancakes and doughnuts were a great way of using up these things. The word shrove is a past tense of the English verb "shrive," which means to confess and therefore Shrove Tuesday gets its name from the shriving (confession) that took place immediately before Lent and is not an old English word for pancake as someone once tried to convince me! Note, just because someone speaks with authority does not necessarily mean they know what they are talking about!
I like my pancakes with lemon juice and sugar and I promise faithfully that I will then give them up for Lent. After all, they get their calories back tomorrow!