The custom of eating pancakes (or similar food) on Mardi Gras or “Fat Tuesday” arose out of the need to use up foods like butter that were generally not consumed during a Lenten fast. While the word fast often conjures up the image of going totally without food what the fast entailed often varied from region to region. Rather than total abstinence from food it was often not eating certain foods like dairy or meat and a general reduction in calories consumed. Nowadays fasting is less common and often involves giving up a single food such as soft drinks or chocolate rather than larger scale limitations.
February 28th is Shrove Tuesday and marks the day before the start of Lent. Shrove Tuesday is also known as Mardi Gras. The most famous Mardi Gras celebration in the U.S. takes places in New Orleans, Louisiana.