Did you know that nearly one quarter of McDonald’s Filet-of-Fish sandwich sales take place during Lent, when many fast-food customers are abstaining from meat? “That’s exactly what the McDonald’s operator who first put the cheese-topped sandwich on his menu had in mind back in 1962. When Cincinnati McDonald’s franchise owner Lou Groen noticed that his heavily Catholic clientele was avoiding his restaurant on Fridays, he suggested to McDonald’s owner Ray Kroc that they add introduce a fish sandwich. That led to a wager between Groen and McDonald’s chief Ray Kroc, who had his own meatless idea. “He called his sandwich the Hula Burger,” Groen said. “It was a cold bun and a slice of pineapple and that was it. Ray said to me, ‘Well, Lou, I’m going to put your fish sandwich on (a menu) for a Friday. But I’m going to put my special sandwich on, too. Whichever sells the most, that’s the one we’ll go with.’ Friday came and the word came out. I won hands down. I sold 350 fish sandwiches that day. Ray never did tell me how his sandwich did.”

The Filet-of-Fish won, the rest is history, Groen’s restaurant thrived, and since then, the sandwich has been McDonald’s fixture, all year long.

Clark, Paul (February 20, 2007). “No fish story: Sandwich saved his McDonald’s”. USA Today.