PepsiCo has quietly gotten rid of the word "Natural" in some of its products and instead is going with "Simply."

The company changed its "Simply Natural" line of Frito-Lay chips to simply be called "Simply," although the ingredients remain the same. Similarly, its "Natural Quaker Granola" got a makeover as "Simply Quaker Granola."

The food and beverage giant says the name changes, which took place last year, are the result of it updating its marketing. But they come at a time when PepsiCo and other companies face legal challenges over their use of the word "natural."

The Food and Drug Administration doesn't have a definition for what constitutes "natural," but says it doesn't object to the word's use as long as the product doesn't contain "added color, artificial flavors or synthetic substances." Still, a number of lawsuits recently have challenged whether the ingredients in products labeled as "natural" fit that billing.

In some cases, companies are realizing the use of "natural" isn't worth the headache, said Steve Gardner, director of litigation for the consumer advocacy group Center for Science in the Public Interest, an advocacy group that has filed lawsuits against companies on the topic.

Last year, PepsiCo agreed to remove the words "all natural" from its Naked juices after a lawsuit noted the drinks contained artificial ingredients, such as a fiber made by Archer Midland Daniels. Another ongoing lawsuit filed in 2012 has challenged its description of some of its chips as "natural." And in November, PepsiCo killed off its Gatorade Natural line, saying the drinks didn't "resonate" with its core consumers.

"We constantly update our marketing and packaging," said Candace Mueller-Medina, a spokeswoman for PepsiCo's Quaker brand.

PepsiCo Inc. isn't alone in retreating from "natural." The owners of Ben & Jerry's and Breyers ice cream agreed to change its packaging in 2012 to settle lawsuits over its use of "all natural." Campbell Soup was sued in 2012 for describing its Pepperidge Farm Goldfish crackers as natural, with the suit noting they contain genetically modified ingredients. The Camden, N.J.-based company removed the word from its revamped packaging, but said it was the result of marketing changes and declined to comment any further on the change.

The word "simply" isn't entirely free of controversy either. Although it didn't file a lawsuit, the Center for Science in the Public Interest met with General Mills in 2010 over labeling on a variety of the company's products. Among those singled out was "Simply Fruit," which the group noted contained canola oil and carrot juice - not just fruit.

When asked if it had a response to the CSPI's complaint that the name was misleading, a General Mills spokesman Mike Siemienas said in an email, "Yes, we do have a response: It isn't."