Recession's over, so who forgot to tell diners?

Despite aggressive promotions, stagnant sales at sit-down restaurants continue to sap overall industry growth.

Restaurant visits have been flat this year, while growth in average check size fueled a 2 percent increase in spending, according to data from market research firm The NPD Group.

"It was said the recession was officially over in 2009, but consumers aren't behaving that way," said NPD restaurant analyst Bonnie Riggs, adding that people are practicing caution and control in their spending.

Consumer confidence declined again last month after a sharp drop in October. Until that metric rebounds and the employment situation improves, Riggs said, industry watchers shouldn't expect to see much traffic growth.

Nicole Miller Regan, a senior restaurant analyst at Piper Jaffray, said restaurants have had "minimum growth" in overall sales, which is "basically at the pace of GDP" growth.

Customers eat at a sandwich shop in Washington.
Andrew Harrer | Bloomberg | Getty Images

"The employed people just don't feel great about spending," Regan said. "It's tightening the wallet. They're going out, but maybe they're spending less or using a coupon."

(Read more: Restaurants' big bet to get you to spend more)

Christine Caraway, a 27-year-old systems coordinator for a bank, falls into this category. While waiting for her order at a Manhattan McDonald's, Caraway said higher meal costs drove her to cut her restaurant visits in half beginning in 2012.

"I'd rather just cook at home," the Brooklynite said. "They've gotten more expensive and the quality's gotten worse."

Growth spot in dining

Full-service casual dining and midscale or family dining spots have continued to struggle this year. The sectors' names include Cracker Barrel, Denny's, DineEquity's IHOP and Applebee's, Darden Restaurants' Olive Garden and Red Lobster, and Brinker International's Chili's.

Fast-food sales rose 1 percent, with gourmet coffee, doughnuts and bagel companies driving much of the growth.

Still, there is a bright spot in the industry this year. Fast-casual restaurants that serve more premium options relatively quickly, such as Chipotle Mexican Grill and Noodles & Co., had an 8 percent traffic jump in the 12 months through September.

Fast-casual growth has been driven by diners like James Gold, a 28-year-old recent graduate school graduate.

Gold eats out about four to five times per week, frequenting Chipotle along with restaurants that serve pizza and ramen.

"It's convenient— it's not terrible fast food," Gold said about the Mexican chain. "So it's almost my go-to for convenient food."

The millennial diner

Millennials cut back on their spending, even though restaurants continue to test mobile ordering and innovative food items aiming at attracting them.

(Read more: Chick-fil-A joins Starbucks in mobile payments bet)

As that age group struggles with record student loan debt and higher relative unemployment, per-capita restaurant visits by 25- to 34-year-olds dropped to 207 this year from 251 in 2008.

In the total population, by comparison, per-capita visits fell to 193 from 208 in that time frame.

Appetizing stocks for investors

"The thing that's really interesting about the industry right now is what's keeping it afloat are not the millennials," Riggs said. "It's the boomers ... who are visiting restaurants more."

Restaurants are making a number of changes to accommodate older diners, including providing more comfortable seating, quieter locations, better lighting and healthier items, she said.

(Read more: McFail: McDonald's out-of-touch tipping advice)

Looking ahead, NPD expects some improvement. By year-end, it estimates, visits on a rolling 12-month basis will rise 1 percent and spending 3 percent.

Despite the tepid sales growth, restaurant stocks have been on a tear. The consumer discretionary sector has been the best performer in the S&P 500 this year, rising 36 percent. Within it, restaurant stocks have jumped 19 percent.

"We've done the math, and the gains are primarily a function of multiple expansion and not because of sales or earnings growth," Regan said. "It's ... really about the equity flows back into the market."

In this environment, she said, stocks of companies with solid brand equity, opportunities for franchise expansion and high-margin licensing opportunities are best poised to outperform the market's growth.

—By CNBC's Katie Little. Follow her on Twitter @KatieLittle.