Subway to roll out all-natural menu by 2017

How do you like your Subway sandwich? If the answer is "6-inch roast beef with no additives," you're in luck.

Subway Restaurants announced Thursday it will eliminate artificial flavors, colors and preservatives from the menu over the next 18 months, joining the ranks of restaurants hoping to cash in on consumer demand for healthy food. Among the axed ingredients is the caramel coloring added to steak and pastrami.

Healthy ingredients draw more customers, according to Nielsen studies, which found that more than 40% of consumers view labels like "all natural" "no artificial colors" and "no artificial flavors" as very important when making purchasing decisions. Yet the build-your-own sandwich giant, which has the most restaurants of any fast-food chain worldwide, has lumbered behind smaller competitors like Taco Bell (YUM) and Panera Bread (PNRA), which also recently announced a nix on artificial ingredients.

Elizabeth Stewart, Subway's director of corporate social responsibility, said converting Subway's large supply chain to all-natural would require "significantly more effort" than smaller chains.

"But, we felt it was important to set an ambitious goal as a means to give us something to shoot for and demonstrate our unwavering commitment to wellness," Stewart said in a company statement.

Though the privately held company behind the "Eat Fresh" slogan had lacked a formal stance on additives, Thursday's announcement builds on the company's previous efforts to evolve a healthy image.

Subway ratcheted up efforts to eliminate additives last year, after Internet activists slammed a chemical found in both Subway bread and yoga mats. After removing artificial transfat as early as 2008, the Connecticut company has since moved to all-natural roast beef and chicken.

Andrew Gewirtz, a professor of biomedical science at Georgia State University, said the movement toward all-natural ingredients is a positive trend.

"There is good data to suggest that food additives are harmful and a logical response to prepare food all-natural," Gewirtz said. "Restaurants should reduce the number of additives. In my opinion there is a sound scientific basis."

Gewirtz's research in mice showed harmful effects from emulsifiers — a type of additive used to keep foods like peanut butter and mayonnaise from separating. Controlling for other ingredients, his team found the amount of emulsifiers in 1 pint of ice cream could promote obesity and related conditions like high blood pressure and high cholesterol.

Still, the Food and Drug Administration (FDA) website says certain levels of food additives are safe and, in fact, can help pack in the vitamins and keep food fresh longer.

Spokeswoman Megan McSeveney said the FDA has a "rigorous premarket approval process" for every food additive and color additive in the entire food supply chain. The safe levels of any food additive used in the U.S. can be looked up on the FDA website.

While there's no guarantee that avoiding additives will lead to a healthier life, Gewirtz said that especially if you're genetically predisposed to obesity or related conditions, you might want to avoid a whole diet of "processed food from a box."

"It's like a wearing seat belt," Gewirtz said. "It's a reasonable way to improve the chances of avoiding a range of illnesses."

Subway just upped its bets that consumers will buckle up for all-natural food — and says it won't raise prices for the additive-free fare.