Protein Bar founder Matt Matros wanted the interior of the first D.C. store, above, to resemble a sleek hotel bar.

Want some quinoa with that?

The South American seed isn’t the typical offering at quick-service food joints, but it’s all over the menu at Protein Bar, a Chicago chain that opens its first D.C. location (at 398 7th St. NW) Wednesday. Offering quinoa — along with whole-wheat flaxseed wraps, chia salad dressing and other nutrient-rich ingredients — helps the restaurant live up to its motto: “We do healthy … healthier.”

And they do quite a bit, including oatmeal bowls, egg scrambles, “bar-ritos,” salads and juices. When founder Matt Matros first opened across the street from the Sears Tower in 2009, the plan was to focus on protein shakes. But when he realized he had no customers at lunchtime, he expanded the food options, which helped him expand the business.

Now, at any of the eight locations in Chicago or the outpost in D.C., there’s something for customers with just about any dietary restriction. The menu clearly labels everything that’s gluten-free, as well as which dishes can be made vegan. It’s been a hit among folks who’ve gone “Paleo” and eat only ingredients that would have been available to cavemen.

Of course, Protein Bar has also lured people watching their weight, which is something Matros knows all about.

“I grew up in LA heavy and heard every fat joke you can imagine,” he says. The low-fat diets that were popular during his youth never worked, so it wasn’t until he graduated from college and decided to try going high-protein, low-carb that he finally managed to slim down.

“I’d go to Subway and peel off the bread. Instead of a bagel in the morning, I’d have a protein bar and green tea,” says the 33-year-old, who credits this diet and his exercise regimen with helping him drop 50 pounds in about six months.

He maintains his figure these days with Protein Bar meals, which boast their nutritional stats right on the menu. He boasts that the bar-ritos have half the calories of popular items at Chipotle. Vitamins aren’t listed, but those numbers look good, too, especially in the salads made with the “Super 6” mix of kale, spinach, romaine, carrots, purple cabbage and broccoli.

“D.C. is an underrated healthy city,” Matros says. “It’s the best for running, and there are so many yoga studios.” So he figures there’s an opportunity to tap into the fitness community to find Protein Bar customers. Expect him to show up at D.C. gyms with a blender to give out smoothie samples — and even to sweat. He’s already taken classes at Biker Barre and joined Vida Fitness.

Washington’s vast population of young people makes the nation’s capital a no-brainer as the next market for Protein Bar, Matros says. A Ballston location will be opening in about six weeks, and he would like to see 15 to 20 branches in the D.C. area eventually.

That’s a whole lot of quinoa.