There's something magical about those golden tubers extending from the bright red McDonald's fry box. Indeed, the iconic golden arches themselves are reminiscent of those delectable fries. They've never pretended to be healthy: a 5.4-oz. (153 g) large order of fries contains 500 calories and more than 38% of your recommended daily fat intake. But the salt-covered, crunchy potato shoestrings have been a McDonald's staple since the fast-food chain's early years, thanks to the combination of Russet Burbank potatoes, vegetable oil, natural flavors and a few other (rather scientific-sounding) ingredients. But those "natural flavors" have come under scrutiny from health and religious organizations. That's because while potatoes are a vegetable, McDonald's fries are bafflingly not vegetarian. In fact, the indescribable flavor of McDonald's fries comes from beef flavoring, a taste that was created by accident in the 1950s when the restaurant's oil supplier mixed in beef fat to its vegetable oil to extend its shelf life. While the recipe has been tweaked since then, mainly for health reasons, the flavor has been maintained. These days, they're cooked with canola oil and the beef flavoring is derived from other sources, but the fries still maintain their crispy goodness.