Why sales of McDonald's Filet-o-Fish sandwiches could surge in next few weeks

Lent started Wednesday and for McDonald's, that could mean a 40-day surge in orders of its Filet-o-Fish sandwich.

According to McDonald's, a quarter of all its Filet-O-Fish sandwiches were sold during Lent last year, as non-meat-eating customers flocked to the chain to get their fast food fix.

Lent is a period of 40 days that begins on Ash Wednesday and ends on Easter. It represents the time that Jesus spent fasting in the wilderness. During this period, many Catholics abstain from eating meat on Fridays.

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In the 1960s, franchise owner Lou Groen from Cincinnati, Ohio noticed a dip in sales on Fridays when local Roman Catholic customers were observing Lent. Groen convinced McDonald's to start selling a breaded whitefish sandwich as an alternative to its classic hamburger.

More than 50 years later, it's still drawing in crowds for that very reason.

Today, the Filet-O-Fish is also a favorite amongst religious Jewish customers.

"The Filet-O-Fish, while not at all kosher, has always been the most kosher non-kosher food at McDonald's," Jonathan Zalman wrote in the Tablet magazine.

Some McDonald's restaurants offer discounts on the Filet-O-Fish on Fridays during Lent.

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