On a recent Tuesday night, Marnie and Jeff Klein bustled into Bubu, the fast-casual restaurant that chef Troy Guard opened last month in Lowry’s Hangar 2.

They set up their 2-year-old son with his iPad, pulled out the menus, and ordered the duck confit buns with hoisin and Chinese vinegar slaw to start. Their boy loves rice and chicken, so there were lots of choices for him on this Asian-inspired menu.

“We’ve been waiting for this place to open,” said Marnie. “We’re so happy to have it in the neighborhood.”

Bubu, which uses the tagline “The Fresh Revolution,” is the latest generation of fast-casual: food by a respected chef, featuring seasonal, health-conscious meals.

The Kleins both work full-time and eat out twice a week. Fast-casual is a favorite because it’s convenient and affordable.

“It’s so easy with him,” she said, gesturing toward her son. “We can get in and get out, and it’s hard for me to get dinner on the table every night.”

Families like the Kleins are helping drive the boom in fast-casual dining, the fastest-growing segment in the restaurant industry that last year hit $38.5 billion in total annual sales, according to the research firm Technomic.

The Denver area, an incubator of this national trend, has the right demographics for fast-casual dining.

“The Denver and Colorado market tends to be the type of person that is looking for something a bit better — natural, fresh and a bit healthier,” said Darren Tristano, executive vice president of Technomic.

Fast-casual is particularly popular with affluent consumers and millennials, he said — and Denver has become the No. 1 destination city for millennials, according to the Brookings Institution.

“But it’s not just the usual appeal with demographic drivers,” said Tristano. “There’s an elevated appeal because there’s been a lot of success in Denver.”

Not just home-grown successes like Chipotle and Smashburger, he said, but “more importantly, brands moving into the space and expanding there.”

Fast-casual restaurants have opened in the Denver area in waves. Chipotle Mexican Grill opened in 1993, followed two years later by Noodles & Company. Most recently, NuHu Mongolian Express and Uncle Joe’s Hong Kong Bistro opened in downtown Denver in the past six weeks.

And Slim Chickens, the fast-casual chicken franchise, will soon open in Boulder.

Feeding busy families

“There’s so much variety now it’s amazing,” said Matt Neren, who dined out one recent evening with his two kids at Larkburger, which happens to be one of his clients at Cultivator Advertising and Design. “Denver is not normal, in the sense of fast- casual choices.”

It’s a cornucopia, fueled by diners like Jeni Planegger, who stopped for a quick dinner at Larkburger in Washington Park with her husband and two young children.

“She had skating until 6:30 tonight, which is why we’re here,” said Planegger, nodding toward her daughter.

They value the quality of the food — all-natural gourmet burgers that are gluten-free except for the brioche bun, which can be substituted with dairy-free and gluten-free buns. When Planegger was pregnant with her youngest, she said, Larkburger was one of the few places she could eat.

“I was gluten-, dairy-, and soy-free because of the baby,” she said.

Larkburger chef-owner Thomas Salamunovich was at the forefront of the latest iteration of fast-casual that touts fine-dining chefs who’ve started fast-casual concepts. Before starting his own place, Salamunovich worked for such culinary superstars as Wolfgang Puck, Paul Bocuse and Jeremiah Tower.

And Bubu’s chef-owner Troy Guard worked with award-winning restaurateur and chef Richard Sandoval, serving as his partner when Sandoval opened the award-winning Latin-Asian fusion restaurant Zengo in Denver, later opening his own restaurants, including Guard and Grace.

Then there’s Bobby Stuckey and Lachlan Mackinnon-Patterson, owners of the fine-dining restaurant Frasca Food & Wine, who own the fast-casual Pizzeria Locale in partnership with Chipotle Mexican Grill.

The ability to get fast-casual meals — where the average per-person receipt runs from $9 to $15 — from top chefs says a lot about the evolution of taste in America.

“Look back to the 1980s,” said David Sax, author of “The Tastemakers: Why We’re Crazy for Cupcakes but Fed Up With Fondue.”

“People who were eating well tended to be well-educated… and knew their French wine,” he said of the decade when the word “foodie” first popped into the American lexicon.

Global food tastes

Today’s fast-casual craze “is about the democratization of food as a cultural force,” he said. “Now your average person living in Stapleton watches the Food Network every night and can go online to get information that was once limited. They know sriracha, and they’ve seen Anthony Bourdain traveling to India. They’re much more exposed to these ideas than they would have been 20 or 30 years ago.”

High-end tastes are now mainstream, and just about everyone is health-conscious. Organic is now de rigueur, widely available everywhere from King Soopers to Walmart. Fast-food places like McDonald’s are scrambling to catch up to fast-casuals that offer customized ingredients — organic, all-natural, or locally sourced — with a certain culinary sophistication.

“They’re definitely on the cutting edge of more global foods, with novel ingredients,” said Suzy Badaracco, president of the Portland-based company Culinary Tides, which tracks the movement of 23 industries to forecast influences on food, flavor, and health trends.

“They’re braver and more risk-taking because their goal is not to translate for the masses and ‘Americanize’ (a cuisine ) but to do it authentically.”

As an example, she cites Noodles & Company.

“The global flavor of each menu item is specific to a region, like the Japanese plate or the Indonesian plate,” she said. “They’re quite true to what dishes might be in those countries.”

During one of the warm-weather days this winter, Wes Dyk sat on the steps of the First Republic building across from Noodles & Company, eating their food with his five-year-old son.

“I wanted something with more vegetables, or healthier,” said Dyk, wearing a T-shirt, jeans, and red-framed sunglasses.

He ordered the pad thai, and his son got the buttered noodles.

Farther up the 16th Street Mall, at Modmarket, Tyler Drake also savored his lunch.

“I’m a big fan of paleo,” he said. “Here I can get steak, sweet potatoes and carrots. At other places, it’s hard not to get bread as part of the mix.”

Modmarket, which started in Boulder in 2009, features food made from scratch, with farm-to-counter quality ingredients.

It’s exactly what he wants.

“If I was my ideal self, I’d cook all my own food,” he said. “But it’s hard to do with work. I’d have to think about breakfast and lunch the night before. This is worth two or three extra bucks.”

Colleen O’Connor: 303-954-1083, coconnor@ denverpost.com or twitter.com/coconnordp