On Monday’s lunch menu at 1600 Pennsylvania Avenue: quinoa salad, cabbage sloppy Joes, baked zucchini fries and, for dessert, a little bubble gum.

Big Time Rush — a four-man boy band made famous on the Nickelodeon series of the same name — gave a short-and-sweet performance at the White House on Monday to close out the first-ever kids’ “state dinner,” a luncheon held for 54 youngsters, ages 8 to 12, who had entered a nationwide recipe contest.

It was the latest event in First Lady Michelle Obama’s “Let’s Move” initiative to fight childhood obesity through healthy eating, exercise and sometimes, music. (“Let’s Move” got a high-profile pop assist last year when Beyonce volunteered a cardio-friendly dance instruction video to the campaign.)

Hosting Monday’s luncheon in a dress the color of electric broccoli and pearls the size of snap peas, the first lady introduced Big Time Rush with hallmark down-to-earthness while staying on message: “They’re awesome, they’re energetic, they’re healthy!”

And once the last strawberry smoothie had been sipped, they were onstage — Carlos Pena Jr. (23, windbreaker), Logan Henderson(22, cardigan), James Maslow (22, vest) and Kendall Schmidt (21, blazer) — cooing “Music Sounds Better With U,” a song that recycles the hook from a semi-obscure, completely wonderful dance anthem by Stardust.

The kids were getting down, quite literally. At the group’s request, they ditched their parents at the various tables across the East Room and quietly huddled on the floor in front of the stage, legs crossed, necks craned. Afterward, Mrs. Obama noted, “At normal state dinners, people do not get to come up front.”

And at normal Big Time Rush concerts, fans do not remain this composed. The band was greeted with the usual ear-wounding banshee yowl at Jiffy Lube Live in Bristow on Sunday night, and they’ll be hearing it again Tuesday at a concert in Virginia Beach.

After Monday’s snappy, three-song set, the quartet shuffled downstairs, savoring the quiet intimacy of the afternoon.

“Everyone is really well behaved,” said Pena. “They did rush the stage, but it was more of a crawl.”

Pena’s band mates said that they weren’t really feeling the butterflies that most singers encounter at the White House. The group took part in Nickelodeon’s “Worldwide Day of Play” on the Ellipse last year, performing for the entire first family, and even challenged Mrs. Obama to a game of Ping-Pong. This time around, the only thing that jangled the singers’ nerves were the whispers between Secret Service agents — who may just have been trying to figure out how to score autographs for their kids.

The group’s tweenage fan base makes them ideal soundtrackers for “Let’s Move,” but they can walk the walk, too. They tour with a personal trainer who makes sure they’re eating lots of green things. “And we burn, like, 3,000 calories a night on stage,” Schmidt said. “We need to be fit or we can’t even do our show.”

It’s one of the more successful shows out on this summer’s tour circuit. Along with One Direction and the Wanted, Big Time Rush complete a trinity of boy bands that have exploded in popularity this year. But the foursome have the self-awareness to know it might not last forever.

“I think everything does have a shelf life,” said Pena. “For us, we’re just taking it day by day.”

For now, the band members are high-fiving over the fact that the first lady sang along to the “whoo-hoo”s of their latest single, “Windows Down.” (The song’s other refrain, “Everybody knows that I want ya,” is surely about pining for more healthful school lunch options.)

After the group took its final bow, children scurried back to their tables wearing big smiles and clutching cameras filled with photos. Never mind screaming — the entire thing went off without so much as a yelp. And nothing matched the gasp that came between the appetizer and the main course when President Obama dropped in for a surprise appearance.

“I heard there was a state dinner,” he told the starry-eyed lunchers. “Usually, I get invited. . . . I had to crash!”