Chef Ludo Lefebvre prepares a pop up dinner at Mel's Diner in Los Angeles
Chef Ludo Lefebvre is seen as he prepares a pop up dinner at Mel's Diner in Los Angeles, California July 29, 2011. From hipster food trucks to exotic menu mashups and "pop-up" restaurants -- reinvention is the theme that connects trend-setting chefs in Los Angeles. Chef Lefebvre, who dazzled diners at some of the finest restaurants in France and Los Angeles, exchanged his chef whites for jeans and a T-shirt and started dining-room surfing. A stint as a guest chef at a friend's eatery inspired what in 2007 became LudoBites, a "pop-up" restaurant, which opens for a brief time, often in a space owned by another operator. Lefebvre and his wife Krissy also star in reality show "Ludo Bites America". Picture taken July 29, 2011. Reuters

Los Angeles' restless and ever-changing food scene is hard to define, but it has forced U.S. diners to rethink their concept of what a restaurant is.

From hipster food trucks to exotic menu mashups and "pop-up" restaurants -- reinvention is the theme that connects trend-setting chefs in the nation's second-largest city that has a reputation as a culinary Wild West.

"L.A. really is the food city of the moment," James Oseland, Saveur magazine's editor-in-chief, told Reuters.

While San Francisco, New York and Chicago have well-defined food identities, Los Angeles' vast, varied and undiluted ethnic food tradition makes it more difficult to pin down.

"The way the global food cultures casually converge in the place makes for a vigorous food culture that exists nowhere else on the planet," said Oseland, who last year devoted a special issue to Los Angeles, dubbing it the ultimate food city.

"It is intensely ephemeral. It mirrors the basic sociology of the city," he added.

The city's best-known chefs are an unruly, unconventional bunch prone to abandoning gigs at five-star restaurants for more offbeat adventures.

Jonathan Gold, a native of L.A. and the first food reviewer to win a Pulitzer Prize, is more likely to visit family-run restaurants in immigrant enclaves than the entertainment industry's latest hot spot.

Kogi Korean BBQ, a Korean taco truck that tweeted its way to international stardom in 2008, is the ultimate example of L.A.'s vibrant food culture.

It was the brainchild of chef Roy Choi, who was a toddler when his family immigrated to the United States from Korea and is now famous for launching the hipster food truck trend that took the United States by storm.

In merging Korean and Mexican fare, Choi put a fresh spin on the working-class "loncheros", or lunch trucks, that have been a staple of L.A.'s bustling street food scene.

He also embraced new technology, networking with food bloggers and tweeting the truck's planned stops.

Choi says L.A.'s non-native cooks are a hard-working and resourceful bunch who quietly have been shaping the city's food culture since the sprawling city was just a pueblo.

"We've been breaking rules for 200 years ... We get resourceful and we do our thing," said Choi, who now has four Kogi trucks and is starting work on his fourth restaurant.

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Chef Ludo Lefebvre, who dazzled diners at some of the finest restaurants in France and Los Angeles with his blend of Old and New World cuisine, exchanged his chef whites for jeans and a T-shirt and started dining-room surfing.

"I wanted to break my image as a fine dining chef and be more accessible," Lefebvre explained.

A stint as a guest chef at a friend's eatery inspired what in 2007 became LudoBites, a "pop-up" restaurant, which opens for a brief time, often in a space owned by another operator.

LudoBites has been one of the hottest dining spots in L.A. Gold dubbed it "a hard-core democratization of cuisine" that is "harder to get into than the UCLA film school".

Lefebvre describes LudoBites as a "touring restaurant" or a "travelling circus".

"I'm scared to be stuck in the kitchen and not be able to travel. With LudoBites I can do my restaurant everywhere I want," said Lefebvre, who is planning a stop in New York City.

The chef and his wife and business partner Krissy Lefebvre just finished a series of one-night shows in places like New Mexico, Alabama and North Carolina.

The couple, who both have reality TV experience, had a camera crew in tow. The results, "Ludo Bites America", air Tuesday nights on the Sundance Channel.

Krissy Lefebvre said the entertainment industry's focus on the next new thing pressures chefs to up their game.

"L.A.'s food scene is inventive because it has to be," she said.