Performers pose during a promotional event of the movie "Iron Man 3" at the Imperial Ancestral Temple in Beijing. The movie includes top Chinese actress Fan Bingbing and some footage shot inside China - additions aimed at tapping into the country's lucrative and booming cinema market. (JASON LEE/Reuters)

Even the nerdiest comic-book fan would be surprised to learn what cutting-edge technology secretly fuels “Iron Man’s” action-packed heroics: a milk-grain drink called Gu Li Duo from China’s Inner Mongolia.

That’s according to the Chinese version of the new blockbuster, which was released here complete with other surprising (read: odd and, at times outright nonsensical) footage inserted by producers to win the favor of Chinese officials.

If aesthetically jarring, the gambit has paid off handsomely. “Iron Man 3” raked in more than $64 million in its first five days and broke Chinese records with its May 1 opening-day haul of $21 million.

It’s a sign of how eager Hollywood has become to court China’s Communist Party leaders, who maintain an iron fist over the country’s booming movie market.

This is how an invading swarm of Chinese soldiers in last year’s “Red Dawn” suddenly became North Koreans. And how Bruce Willis’s character mysteriously came to spend much more time in Shanghai than Paris in last year’s “Looper.” And why the outbreak sparking the zombie apocalypse in Brad Pitt’s “World War Z” this summer has been rewritten to originate from Moscow instead of China.

U.S. producers often spin such tweaks as an attempt to appeal to Chinese viewers. But experts say their more crucial target is the Chinese government’s 37-member censorship board, which each year approves just 34 foreign films for Chinese screens and reviews all their content. With China becoming the world’s second-largest box office market last year, failing to make that list can mean the loss of tens of millions of dollars.

U.S. film executives have described a process that involves heavy negotiation and wooing as they try to win approval. To please the authorities, studios have been willing to add Chinese actors, locations and elements to their cast, adjust release dates and tweak plot points to flatter or at least avoid offending Chinese officials.

It has been tough, however, to predict exactly what will tick off Chinese party censors, who often flag scenes not only for violence and nudity but also political sensitivity.

They have at times fixated on small details such as shots of unsightly laundry hanging from Shanghai residences in “Mission Impossible 3” and a passing reference to the Cold War in one line of a James Bond film. Time-travel dramas were inexplicably but effectively banned in 2011 by Chinese authorities, who called it “disrespectful of history.”

But the government board has sometimes surprised as well, raising eyebrows for instance when it greenlighted last year’s “Hunger Games” — a movie about an authoritarian government that represses its people using a combination of propaganda and brutal force.

The latest cautionary tale came last month when Quentin Tarantino’s “Django Unchained” was yanked from some Chinese theaters as the movie was rolling on opening night in China.

Was the problem those geysers of blood in the revenge fantasy flick? (Tarantino had already toned down the color and splatter to a more modest fountain, a Sony official told a Chinese newspaper.) Was it the scenes of repressed slaves rising to overthrow masters (always a touchy subject here where party leaders live in fear of revolution)? The exact reason has not been explained, but the film’s release has been rescheduled for May 12.

The stakes are high. Chinese box-office revenues grew 30 percent last year to $2.77 billion, and the Motion Picture Association of America has predicted China will overtake the United States as the biggest movie market by 2020.

From the beginning, the makers of “Iron Man 3” took no chances, setting what may be a new bar for accommodating Chinese officials.

They made the movie a joint venture, teaming with Beijing-based DMG Entertainment. Government officials were invited on set to monitor filming. The name of Ben Kingsley’s villain, the Mandarin, was stripped of any Chinese association by transliterating his name as “Man Daren,” which has no meaning in Chinese.

The most jarring changes, however, were a few minutes of footage added to the film, including the opening plug for the drink from an Inner Mongolia-based company — a sweet mixture of milk, grains and food additives — which viewers are told, via a commercial-like bit of bold text stripped across the screen, can revitalize Iron Man’s energy.

Other added scenes — which make only slightly more sense — feature a Chinese doctor and his unnamed assistant, played by one of China’s most popular actresses, Fan Bingbing. Some of the film’s most over-the-top dialogue comes when the two discuss how the world’s expectations and the life of Marvel’s lucrative hero hinge on them and their unique Chinese medical abilities.

While Chinese audiences have flocked to theaters, the extra footage has sparked much ridicule online and even within party-controlled media. Some called the Chinese actors’ token screen time insulting. Others mocked the filmmakers for apparently selling out to the government.

One microblogger named Bumblebee Marz compared the new scenes to chicken ribs — a common expression denoting the most tasteless and undesirable cut of meat in Chinese cuisine. “Not essential at all,” the blogger said.

Meanwhile, other studios are racing to go even further. The makers of next year’s “Transformers 4” have come out with a new idea to increase their own China-friendly quotient: a reality TV contest in China that will award four winners speaking roles opposite the robots.

Expressing a common disregard for Michael Bay productions that seems to transcend national borders, one Chinese microblogger under the handle ZaoanWuanWanan coolly observed, “the Transformers series just keeps degenerating.”

Li Qi in Beijing contributed to this report.