Greek yogurt, the thick, creamy, protein-packed dairy product, has stormed supermarket shelves in the United States. The breakfast favorite's astonishingly fast growth is epitomized by the success of Chobani—perhaps the best known brand: the company, which began selling Greek yogurt in 2007, saw its sales skyrocket from just over $3 million to more than $1.1 billion in its first five years. Today, Greek Yogurt accounts for roughly half of all yogurt sales in the United States, which is remarkable considering that it was essentially irrelevant less than a decade ago.

But popularity in the American food world can be a fickle thing, and the Greek yogurt business is learning that first hand.

After years of double digit growth, Americans' enthusiasm for the trendy yogurt seems to be cooling. PepsiCo recently announced that it was ending its U.S. production of Müller, a German yogurt brand known in part for its Greek yogurt offering, after sales continued to disappoint. Chobani, meanwhile, is facing something that seemed unfathomable only a few years ago: a slowing business. After a disappointing 2014, in which sales were flat compared to the year prior, 2015 began tepidly. As of earlier this year, the company was expected to see its annual sales fall for the first time ever, according to market research firm Euromonitor. (Chobani says that business has been much stronger since, and that the company expects sales to grow year-over-year).

"It's undeniable that Greek yogurt sales have noticeably begun to mature," said a recent analysis by Packaged Facts, an industry research group, which contemplated what the next big yogurt innovation might be.

In this context, mature means evolve—not away from the broader Greek yogurt category, but away from its bread and butter: the simple, straight forward food, sometimes livened with a touch of something sweet. This isn't to say that Americans aren't still spooning the creamy yogurt into bowls—Chobani's yogurt tubs and single serving packets are still the industry's strongest offering, and the category overall is still growing—albeit by a modest 5 percent, according to data from Nielsen. But the no-frills product that won over America's stomachs—at least in the morning—is less new and exciting than it once was. Just three years ago, industry growth towered above 60 percent.

"Old fashioned Greek yogurt is definitely losing some steam," said Jared Koerten, who is a senior food analyst at Euromonitor. "This is something we have been seeing for a couple years now."

Mostly, the slowdown is a simple matter of fatigue. Americans, having learned about and loved a new food, are now looking for the next thing as they are wont to do. "We grow tired of things pretty quickly here in the United States," said Koerten, who reminds that not long ago frozen yogurt was atop the ice cream world (it's now "facing oblivion").

It's also the result of an increasingly crowded breakfast space. Once a simple meal, centered around cereal, milk, and orange juice (thanks, in large part, to marketing), breakfast now comes in many and varied forms. Greek yogurt has been a staple of this mutation, soaring as cereal has faded.

The prevalence of other options has made it easy for people to try something new, and then stick with it if it suits. The clearest evidence can be found at fast food companies like McDonald's, where the sales pitch is mostly egg sandwiches, and the morning meal is growing faster than any other segment of the day. Restaurants as a whole, in fact, are enjoying something of a breakfast boom, while people are going out less often for lunch and dinner. 

"The good news is that there doesn't seem to be a next big thing," said Koerten. "The breakfast space is very saturated at this point, but there's nothing really right now that has the sort of potential Greek yogurt did ten years ago."

Rather than wait until something new pops up or watch as its core product loses its novelty, the Greek yogurt industry is working to make sure it stays relevant. Manufacturers have adjusted their strategy to focus on innovation, addressing both the reality of customer fatigue and the latent possibility of luring Americans into eating the protein-heavy food at other times of the day.

For some companies, that has meant expanding flavor offerings (Yoplait's Greek yogurt lineup, for instance, now runs 16 flavors deep). For others, it has involved selling smaller, calorie-controlled portions (100 calorie packages have proven wildly popular), or doubling down on ingredients associated with wellness and health.

For Chobani, the approach has been a combination of bolstering its staples, which are eating up more and more of the Greek yogurt market, and introducing new products to see what sticks. The largest seller of Greek yogurt has looked out for its bottom line by launching new products and iterations.

Flip, the company's new offering, is evidence that the strategy can work surprisingly well, even when the tweak is comparatively tiny. The snack food, which comes in a two-part plastic container (one part for Greek yogurt, the other for what Chobani calls "real, delicious ingredients"), mimics formerly popular yogurt products, which came with a separated topping of granola, nuts, and other goodies. When you fold the malleable container in half, the toppings spill into the yogurt.

"People have absolutely loved them," said Koerten, who admitted that the success of Flips has been somewhat surprising. "From what I've heard, sales have been up ever since they launched in June. They might even flatten out as a result by the end of the year."

But just because minor tweaks seem to be working today doesn't mean they will tomorrow. If Chobani is going to convince Americans to eat Greek yogurt all the time—at breakfast, lunch and dinner, as well as throughout the day as a snack—it will likely have to introduce a few weird things too.

Enter the soon-to-come iteration of Flips, which Chobani is launching early next year. The new line, which will include flavors like Sriracha-Mango, is meant to challenge American palates in ways previous taste profiles have not (mango yogurt, for example, will come paired with sriracha roasted rice crisps, mini sesame sticks, and salted cashews).

If all goes well, it will also get people to think about Greek yogurt as less of a stubborn, single purpose food, and more of a staple that can serve all kinds of different cravings throughout the day.

This story has been updated to reflect that Euromonitor's estimates were calculated earlier this year. Chobani expects its business to grow—not shrink—in 2015.