Kale, flax, Greek yogurt—some of fast food's latest creations have all the makings of an aisle at your local Whole Foods Market.
To adapt to shifting customer tastes, restaurant giants are debuting foods that a decade ago would have been more likely relegated to a natural foods market than advertised next to the dollar menu.
Wendy's is one recent example of a chain testing out a super food, items that are known for being nutrient packed.
"We just tested a salad a few months ago—spinach, chicken with quinoa," said Wendy's Chief Marketing Officer Brandon Solano in an interview. "We're really trying to push the envelope."
"What we have to balance at Wendy's is something that's leading-edge culinary that's still going to be accepted across mainstream," Solano added. "We're a mass brand so we're always trying to walk that line."
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Meanwhile, rival McDonald's is planning to incorporate kale into its menu in the not-too distant future, wrote Janney Capital Markets analysts in a recent note.
"We're always looking at new and different ingredients that customers may enjoy," spokeswoman Lisa McComb said in an email, while declining to confirm the chain will be using the trendy leaf.
The broader restaurant industry has already jumped on the bandwagon, fueling a sharp rise in these better-for-you items on menus. During the past five years, quinoa appearances on menus have surged 1,200 percent, kale 1,100 percent and Greek yogurt 900 percent, according to Technomic's MenuMonitor.
At least two large fast food chains are testing whether the rise in Greek yogurt seen in the grocery aisle will translate into higher sales at the drive thru. This summer, Yum Brands' Taco Bell said it would be testing Greek yogurt made with natural ingredients with a premium granola topping in Omaha, Nebraska.
Known more for its breaded chicken and waffle fries, privately held Chick-fil-A also tiptoed into the Greek yogurt waters. A parfait creamy honey vanilla twist on the tart item started testing in greater Philadelphia, Inland Empire, California, Middle Georgia and Memphis, Tennessee last summer. It also tried out a steel-cut oatmeal dish with flax and buckwheat.
Some of fast food's new, healthful items are aimed as much at driving incremental sales as they are at boosting a brand's image, said Larry Light, CEO of consulting firm Arcature. Previously global chief marketing officer at McDonald's, Light helped worked on the introduction of premium salads at the Golden Arches.
"If we only look at sales of an individual item, we can underestimate the value to the brand," he added in a phone interview.
Meanwhile, restaurant consultant Aaron Allen sees the addition of healthful food as a reaction to the sharp growth of fast-casual, which sells premium ingredients at less expensive prices than full-service dining and at speeds similar to fast food.
It also coming amid broader trends toward simplification, responsibly raised foods and fewer chemicals and antibiotics used in meat production, he added.
"It is a smart move, but they should have done this years ago," he said. "In some cases, it might be too little, too late."