A clean food revolution is sweeping fast food, but Panera's CEO still has one major concern

Panera Bread has finally completed its mission to make its menu 100% "clean," cutting all 96 additives and ingredients the company identified on its "No No List" two years ago.

"When we made the commitment, we weren't sure we could get there," CEO Ron Shaich told Business Insider.

Panera first announced its plan to cut all artificial ingredients in May 2015. With the completion of its promise, Panera became the first national chain to complete such as overarching commitment.

Over the last two years, going at least partially "clean" has become almost expected in the restaurant industry.

McDonald's has recently replaced margarine for butter in its breakfast sandwiches and cut artificial ingredients from McNuggets. As of July, Papa John's is exclusively using poultry raised without antibiotics and fed a vegetarian diet for grilled-chicken pizza toppings and chicken poppers. And, in 2015, Taco Bell cut all artificial ingredients from the menu, except those used in co-branded products like Doritos Locos Tacos.

While Shaich believes chains' decisions to cut some artificial ingredients are "better than nothing," he thinks that certain chains are "watering down" the value of the term clean by not fully banning artificial ingredients altogether.

"That destroys it for all of us," Shaich said.

There also is no industry-wide definition of what "clean" food is, which complicates things, according to Shaich.

"We would prefer [clean] to be a defined term," he said.

Emphasizing that some menu items are "clean" and "all-natural," instead of cutting all artificial ingredients or focusing on hard nutritional figures, gives chains more flexibility with what fits under the umbrella of healthy - something that Shaich believes can weaken the power of the phrase.

Ultimately, Shaich says that customers can discern between chains that only go "halfway" and those that commit fully to a clean menu.

Further, he says that Panera's clean menu policy isn't about the competition. It's about looking beyond the current trends to better understand what customers want next.

"It's gratifying to know that the bets that you made generally played out to be wise bets," said Shaich. "What I'm paid to do as CEO, what the leadership at Panera spends its time working on, is figuring out where is the world going to be for our guests in the next two to five years, and making sure Panera is there when it gets there. They don't pay us to react to yesterday."