Many of these items are offered only for a limited time, which encourages customers to get them while they're still hot (and available.) They're also often geared toward attracting younger pockets.
"Younger consumers tend to be more engaged in trying off-the-beaten-path items," Tristano added. "This has given rise to some over-the-top new items that can be characterized as over-indulgent sizes and flaming hot flavors."
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Sky-high beef prices are also contributing to some changes on restaurant menus. Earlier this week, McDonald's announced it would be replacing its Angus Third Pounders with three new Quarter Pounders that contain less beef. While two varieties, bacon and cheese and deluxe, would remain the same as the Angus burgers, the third one would be of the spicy variety sought out by younger audiences—a Habanero Ranch burger.
Some of the innovation that restaurants are rolling out is more evolutionary that revolutionary, said Nicole Miller Regan, senior research analyst at Piper Jaffray.
For example, Olive Garden hawked its menu centered mostly around pasta and breadsticks for years even as many consumers embraced low-carb or gluten-free lifestyles.
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"Olive Garden kept on doing the same thing over and over again, but at some point the market changed," Regan said.
"You can be static and do more of the same as long as it's working, but it's going to work until it doesn't," she added.
The company, which is owned by Darden Restaurants, saw its U.S. same store sales decrease 1.2 percent in fiscal year 2012 before it began implementing a slew of changes at its stores, including new lighter Italian options, remodeled restaurants and lower prices.
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Burger King also tried to fill in its menu gaps by adding new salads and expanding its chicken offerings last year and planning a rival to the extremely popular McDonald's McRib sandwich set to debut this summer.
Still, Regan said, "I think Burger King is still at the point in their life cycle of catching up."