There was mood-rock and muffuletta. Electro and gazpacho. Power-pop and pickled peppers.

The summer concert season kicked off at Merriweather Post Pavilion on Saturday in a synaesthetic swirl during the third annual Sweetlife Food and Music Festival, an 11-hour affair featuring a fleet of food trucks and 20 musical acts, including Swedish house hero Avicii, rock vets the Shins, rapper-crooner Kid Cudi, goth-pop chanteuse Zola Jesus and others.

The festival’s foodie/indie culture merger sounds like something worthy of a “Portlandia” sketch, spoofing America’s burgeoning 20-something hipster class. But instead, Merriweather was teeming with teenagers. Many wore high school varsity sweatshirts and wide-eyed looks that seemed to say, This is my first concert and l’mhavingsomuchfunrightnow.

With all of those adolescent endorphins coursing through the damp April air, the festival’s genre-jumble lineup didn’t seem as haphazardly curated as it did on paper. With thousands of fans enthusiastically shouting along to whoever was onstage, switching gears from the rousing pop-rock of the hit-band Fun. to the ethereal rap anthems of A$AP Rocky felt completely natural.

But those two standout performances came early in the day, which was too bad, considering scores of fans were still dawdling around the festival’s phalanx of food trucks, trying to decide among gourmet pizzas, grass-fed beef sliders and fancy grilled cheeses.

Decisions, decisions. But here’s an easy one: Merriweather should invite these food trucks back for every concert this summer.

The only drawback was that over-noshing made the middle of the day feel like nap time. Los Angeles soul-revivalists Fitz and the Tantrums valiantly tried to rouse the audience from its collective food coma, but the band didn’t manage to spark the dancing its music deserved. Explosions in the Sky — the instrumental-rock band famous for scoring the television show “Friday Night Lights” — didn’t help the situation. The group’s guitar-centric rock songs would repeatedly twinkle, then explode into blandness.

It was followed by the Shins, who provided the evening’s most pleasant surprise by injecting their cuddly, soft-rock tunes with a little spark and sweat. The sun was setting, the rain was falling and everyone was awake again.

Beyond the Merriweather lawn, equally disparate acts had been hammering it out all day on the festival’s second stage, where sporadic rains put fans’ faith to the test. “We are not wet, and we are not cold,” Zola Jesus told a loyal audience as she paced the stage. “Nope!”

Backed by a keyboardist, a percussionist and a violinist, she pumped her arms to a series of dark, electronic pop songs, as if conducting a phantom orchestra, and she sang in a voice that was every bit as commanding. It was the type of performance that hit reset on your eardrums and made a lot of what came after feel inconsequential.

That meant that New York’s Twin Shadow sounded like the Cure watered down in crocodile tears. And down on the main stage, Kid Cudi’s sensitive-guy rap was as profound as anything you might find inside a fortune cookie. But the crowd hung on his every lyric — even when those lyrics were “This is the soundtrack to my life!” and “Always had my back, hey, marijuana!”

Avicii, the ascendant DJ and producer, was the festival’s headliner and its biggest outlier. Sporting a backward-turned baseball cap and a white hoodie, the 22-year-old looked like a J.C. Penney model circa 1993. But his music was more fashionable, epitomizing the pulsing beats and sugary melodies that have made devout dance music fans out of so many young people in the past year.

It was a fitting finale — sweet like sorbet and kicky like cappuccino.