DUBAI, United Arab Emirates — Friday will never be the same again.

For those with means in Dubai, the former first day of the weekend carried a gluttonous party tradition — an hourslong affair with infinite supply of seafood, pizza, dessert and Veuve Clicquot Champagne set to pulsing music known simply in this city-state as “Friday brunch.”

But starting this year, the United Arab Emirates shifted its weekend from Friday and Saturday to Saturday and Sunday — a move to align with global markets and Western schedules.

Now, Emirati government employees work a half day with time for worship and family gatherings on Islam’s holy day. Most of the nation’s expatriate-dominated private sector, however, works the full day.

That has thrown Dubai’s beloved Friday brunch — a key revenue source for COVID-19-battered restaurants that revel in Instagram-worthy, booze-soaked buffets — into disarray.

“The traditional 12 p.m. Friday brunch is extinct,” said Adrian John, who along with his wife Lucy Melts started a popular Dubai brunch review website called Mr. and Mrs. Brunch.

Friday brunch in Dubai involves far more than the midday meals enjoyed in other major cities like New York and London. For those not rendered immobile after four hours of feasting, there’s the post-brunch brunch, evening brunch with more booze and midnight party brunch.

“It’s the experience Dubai is known for. It helped put Dubai on the map,” said Samantha Wood of the Foo­Diva restaurant review website.

Luxury hotels and restaurants each have their own brunch style. One steakhouse offers a James Bond theme with a background of spy movie music. Cash rains from the ceiling of the Waldorf Astoria hotel at a brunch inspired by the Martin Scorsese film “The Wolf of Wall Street.”

There is a karaoke brunch boasting lip-sync battles and another featuring a giant spread of lamb shanks beside a petting zoo. Hotels roll out dessert trays with chocolate fountains evocative of Willy Wonka.

The fixed prices may seem expensive — all-you-can-drink Champagne packages cost over $200 — but cheaper options exist. Devotees insist that unlimited booze remains a deal in a city where every drink poured in a bar is subject to a 30% municipality tax.

Brunch spots also have their own clientele. At CÉ LA VI, a sprawling rooftop with an infinity pool and stunning views of the Burj Khalifa, the tallest tower on the planet, a group of Russian tourists cloaked in Balenciaga leather strained their necks to snap selfies on a recent Saturday morning. Businessmen flashed Rolexes as they loaded up on Parker House rolls. A table of well-coiffed young women debated the best place to get breast implants.

At Filia, a lower-key Italian spot at the SLS Hotel downtown, a group of expat mothers picked Parmesan from a dish the size of a car wheel and shouted to be heard over the DJ’s deafening party tunes.

Locked in a culinary arms race to attract Dubai’s big spenders, brunch destinations are now keen to keep the extravaganza alive despite the weekend upheaval.

The industry has sought to remake itself with a new tagline: “Saturday is the new Friday.” Any Sunday brunch would serve as a hangover breakfast, managers say, a family friendly affair to recover and launch the week with quick appetizers and light mimosas.

“People party on weekends, so naturally Saturday should be the new party brunch,” said Andrea Sacchi, the chief operating officer of the upscale Roberto’s Restaurant & Lounge in the glitzy Dubai International Financial Center. “We changed the branding, collateral, scheduling, reservation systems.”

But uncertainty reigns as residents mourn the loss of a Dubai rite.

“There’s an element of sadness,” said Melts, the other half of Mr. and Mrs. Brunch, who came to Dubai 12 years ago from Reading, England. “It was so nice to be different from the world, to be like: ‘Look, it’s Friday, we’re brunching while our friends back home are working.'”

Without Friday, restaurant executives wonder whether Dubai brunch can keep its luster.

Since the change took effect on Jan. 2, many of Dubai’s hottest brunch spots have felt lukewarm.

“The numbers are not that great at the moment on Saturdays compared to last year,” said Arun Edakkeppurath, manager of the glass-enclosed Observatory Bar & Grill with drop-dead views of Dubai’s Palm Jumeirah artificial island.

The restaurant now receives a flood of calls from bewildered government employees, teachers and others who work a half-day on Friday, demanding to know what happened to their famous brunch.

“I think people will react slowly to the changes,” he added.

Other brunch places have reported empty tables since the weekend shift.

“There have been a large amount of cancellations,” said Sadhan Adhilkary, assistant restaurant manager of Jazz@PizzaExpress, which scrambled this year to push its brunch to Saturday and rebook its music acts for Friday, the new party night. “But it’s hard to say the reason.”

Business usually slows as residents tighten their belts after New Year’s Eve spending binges, he said. A sense of trepidation also has returned to the pandemic-era boomtown as the omicron variant drives a major surge in infections.

Industry-wide, “we still really don’t know how people will react,” said Nicolas Budzynski, LPM Restaurant & Bar’s global operations director. “I think there is anxiety. It has created some confusion.”

LPM has moved its classic brunch to Sunday, betting that Saturdays will be overscheduled with errands and Sundays will be better suited to festivities and family gatherings.

“I can tell you that Saturday is not the new Friday,” he argued. “It doesn’t replace a day that was quiet only because of prayers.”

John, who still reminisces about the all-you-can-drink brunch on a luxury yacht where he met Mrs. Brunch over a decade ago, believes Friday had a magic formula for success that may never be regained.

“I remember being fresh off the boat, thinking: ‘Wow, what is place? This is amazing, this is just brilliant,'” he said. “Friday brunch will always be something romantic. We’ll always have those years.”