While French fries are a staple of the fast-food burger business, they have long been vilified by nutrition experts as little more than vehicles for adding fat, salt and calories to diets.
Now Burger King has come up with a fry that it says delivers about 40 percent less fat and 30 percent fewer calories than the fries sold by its archenemy McDonald's. Burger King says that 70 grams of its new fries, named Satisfries, has 150 calories, while the same amount of McDonald's fries has 226 calories.
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"You live in Manhattan and might be having a kale smoothie on your way to work this morning," said Eric Hirschhorn, chief marketing officer for Burger King, the nation's No. 3 hamburger chain after McDonald's and Wendy's. "But a lot of people don't even know what kale is, and if they do, they don't want to eat it. You have to give people what they want."
Burger King, which has struggled as a series of owners traded it like a baseball card, was late to try to improve the nutritional quality of its food.
But under its newest owner, the private equity group 3G Capital, the chain has invested time and money in retooling its menu over the last two years, adding choices like cranberry apple salads and mango smoothies and taking one of two slices of cheese off its burgers in the biggest changes to its menu since opening in 1954.
"Behavior doesn't change as quick as attitudes," Mr. Hirschhorn said. "It's easy to put things on a menu and check off the box, but the reality is that nobody buys them."
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Roughly a decade ago, McDonald's began using a soy-corn blend of fats instead of beef tallow to cook its fries in an effort to reduce the trans fats that contribute to higher cholesterol.
More than 100 million customers eat in a Burger King store each month, and 56 million of them order fries. While the chain had made minor adjustments, offering healthier sweet potato fries and curly fries, nothing matched the scale of reinventing the fries.
French fries served in fast-food settings are coated with a thin batter that seals in flavor and moisture and enhances exterior crunch. Burger King spent the last two years working with McCain Foods, its French fry supplier, to develop a batter that was less porous and would therefore absorb less fat in the frying process.
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The new fries will be crinkled, so that Burger King staff can distinguish them from their full-fat cousins, which will continue to be sold. The chain's meals for children will offer them at no extra charge, but Burger King is recommending that its franchisees add 20 cents to 30 cents to the price for adults.
"On its own, this may seem like a small step," Mr. Hirschhorn said. "But we think it can add up to something big."