The Double Down has 540 calories and 1,300 milligrams of sodium. While it was being test marketed, demand for the Double Down proved so strong that there were reports of people driving across state lines to try it. Americans purchased some 10 million of the sandwiches in the first month they were offered nationwide.
"Marketers know that there is an infinite appetite for these kinds of products, so they're going to just keep piling it on until finally, consumers say, 'OK! You went too far. I really want a salad!'" said Drew Neisser, a marketing expert from the advertising firm Renegade.
But American consumers have yet to make that call, and demand for monster burgers is so strong that some are even devising their own super-sized burgers.
A McDonald's burger has gained a cult following on the Internet, even though it isn't even on the menu. It's a concoction of McDonald's dollar menu products, consisting of a double cheeseburger with a spicy chicken sandwich in the middle, and it's got a profane nickname that can't be printed here.
Many have posted videos of themselves ordering and eating the sandwich on YouTube, making it an 800-calorie viral and culinary sensation.