The restaurant company said that by next month all of its pork supply will be fed only a vegetarian diet, never be given any antibiotics, and that the farms that supply its pigs will not use gestation crates on pregnant sows. It also noted that 80% of the beef it served in 2014 was grass-fed, and 18% of the 70 million eggs served were cage-free. Panera has used antibiotic-free chicken since 2004, but this year all of its roasted turkey met the same standard.

Panera first published its food policy in June, announcing its commitment to “clean ingredients.” As part of the move, the company said it would remove artificial colors, sweeteners, flavors, and preservatives from its food by 2016. (It had already removed artificial trans fats from all but one item.)

At the time of the initial announcement, I wrote about how the policy was a reflection of a changing definition of health—that wellness today is not just about fat and calories but also about where our food comes from. “Now [consumers] want to know how food is raised,” says Darren Tristano of industry research firm Technomic. Issues tied to the humane treatment of animals, like free-range, give people an emotional connection to their food and another reason to buy, he adds.

Because that changing definition of health is being driven by Millennial customers, Tristano notes that the initiative from Panera is in part a move to attract younger consumers. “What’s driving it is the mistrust of consumers with restaurants, and particularly the younger generation, [which] is looking for greater transparency,” he says.

In an interview with Fortune, Blaine Hurst, Panera’s chief transformation officer, stressed the company’s desire to be an “ally for wellness” with its customers. “There’s so much noise out there and so many people telling us so many different things,” says Hurst. “What we want you to be able to count on as a consumer is that we’re there for you in this journey of wellness.”

Panera senior vice president of food Dan Kish noted that the company’s updated food policy is also linked to taste. “Animals that are raised in environments with reduced confinement and stress yield a better raw material for us to work with,” he says.

Technomic’s Tristano says that Panera (PNRA) is ahead of the curve on this front. “The brands that are more successful and thriving can afford to invest in supply chain,” he says. “It’s an investment in the long term.”

The company most often held up as the premier example on these issues is Chipotle (CMG), whose “Food with Integrity” campaign promotes the fact that its meat is raised without hormones and antibiotics when “possible” and local and organic produce is used when “practical.”

Carl’s Jr. is also jumping into the game, rolling out a burger made with an “all-natural, grass-fed, free-range beef patty that has no added hormones, antibiotics, or steroids.” In a press release, the company touted that it was the first major fast-food chain to offer an all-natural beef burger and that its decision was driven by a “growing demand for ‘cleaner,’ more natural food, particularly among Millennials.”

McDonald’s (MCD), which is suffering through one of its worst years in more than a decade, hinted at its investor meeting last week that it’s looking to make progress in this department by simplifying ingredients. For example, Mike Andres, president of the company’s U.S. business, said that its food probably didn’t need preservatives.