That's not going to be an easy sell, because it's been tried before.

Ever since it was founded, in 1964, Arby's has prided itself on offering a different sort of fast food -- namely, roast beef sandwiches, which are really yummy. The company, though, is proud that it was the first fast-food chain to offer a "complete light menu" in 1991. 

Ten years later, the company expanded its healthier offerings and introduced the Market Fresh line of sandwiches and salads. In 2008, Wendy's agreed to be acquired by Nelson Pelz's Triac, which controlled Arby's. The company took the Wendy's name, and the Arby's chain languished for years. The company tried pushing the freshness of its food again last year with its "Good Mood Food" campaign, but the message didn't stick.

"The fact that Arby's has been freshly slicing meats in every restaurant for nearly 50 years is something we're extremely proud of, and it's something not all restaurant chains can say they do for their customers," said Russ Klein, the chief marketing officer of Arby's Restaurant Group.

One chain that can make that claim is Subway, which tops the list of Zagat's favorite mega-fast-food chains. Subway has effectively branded itself as a purveyor of healthful food, though some of its menu items are better choices than others. McDonald's (MCD) is also marketing its healthier fare, as is Burger King (BKW), all spurred on by growing public concern about obesity, particularly among children.

Whether Arby's, which has more than 3,500 locations, can differentiate itself from much larger rivals Burger King (12,500) McDonald's (33,500) and Subway (37,776) remains to be seen.

As Bloomberg News noted, Arby's new campaign targets diners who eat out about 50 times a month but dine at the chain only about six times during that period. They represent 20% of Arby's customers and account for two-thirds of its total transactions. Winning them over may not be easy.

So far, at least, fast-food fans don't appear to be overly impressed with Arby's. For instance, Brand Eating found the Arby's Turkey Classic to be "too plain to be a good vehicle for turkey."

All the marketing campaigns won't mean squat if people don't like the food.