WASHINGTON -- The world's largest food industry lobbying group is waging a stealth campaign to discredit the highly anticipated anti-obesity documentary "Fed Up," which opens in theaters Friday.

The film was produced by Katie Couric and Laurie David, who was a producer of the Oscar-winning documentary "An Inconvenient Truth." "Fed Up" investigates the root causes of America's obesity epidemic, drawing special attention to how the processed food industry's aggressive lobbying and advertising have contributed to the problem.

But people looking online for information about the movie could be in for a surprise. Days before the film's release, a new website appeared that at first looks nearly identical to the official "Fed Up" site. But instead of featuring the movie trailer and showtimes, the site adopts the popular online quiz format, luring people in with a challenge: "Think you know the facts about 'Fed Up?' Take the quiz."

The "quiz," it turns out, is nine "true or false" questions. Six of them are statements made by doctors and food policy experts in "Fed Up," such as, "Food companies have caused the obesity rate to skyrocket." If you click "true," you'll get a big, fat "incorrect," and below that, some selectively edited figures about obesity rates. The other three questions are about the food industry, and the steps it claims to have taken to combat obesity. The correct answer for these is "true."

One of the "quiz" questions on the fake "Fed Up" site.

As for who is behind this propaganda page for the food processing industry, say hello to the Grocery Manufacturers Association (GMA), the primary lobbying group for the nation's largest food and beverage companies.

The lobbying group launched the dummy website, called FedUpFacts.com, on Wednesday, the same day it purchased Google ads for search terms related to the documentary, including its title. The ads direct back to the quiz site, where there is a disclosure notice at the bottom of the page: "FedUpFacts is brought to you by the Grocery Manufacturers Association, representing the makers of the world's favorite food, beverage and consumer products."

The phenomenon of decoy websites intended to mislead isn't new in politics, but it remains a controversial tactic. The notion that an industry lobby would use a dummy site to attack a Hollywood movie, however, is highly unusual.

In a joint statement, Couric, David and "Fed Up" director Stephanie Soechtig said the GMA sham website "borders on outright lying." By using tactics like these, they added, GMA is "taking a page right out of Big Tobacco's play book."

GMA spokeswoman Ginny Smith said the group had no intention of misleading visitors, and that the website was created "to provide consumers with clear, credible information about the food industry. This includes clearly identifying GMA as the sponsor."

Even so, there are plenty of more efficient ways to get a message out than through a heavily biased quiz on a website created to mirror an opponent's site. For instance, GMA could have just agreed to the request for an interview it received from Couric and the other "Fed Up" filmmakers. But the lobbyists refused, as did scores of companies that are members of GMA.

In fact, the list of people who declined to be interviewed for "Fed Up" is so long that scrolling through the names on the screen is one of the film's most sobering moments. Smith, the GMA spokeswoman, said the group declined because "it was clear [the filmmakers] had already determined their narrative, which did not include a balanced view of the food industry."

Controversial or contentious interviews can be potentially lethal for food and beverage companies, which still rely more heavily than other companies on individual consumers and brand loyalties, making the companies highly vulnerable to any whiff of negative publicity. Not surprisingly, as of Friday, not one of the GMA's member companies, or the food companies mentioned in the film, had publicly commented on it.

Instead, they looked to GMA President and CEO Pamela Bailey to address controversial topics on their behalf. Bailey issued a statement this week critical of "Fed Up."

"Rather than identifying successful policies or ongoing efforts to find real and practical solutions to obesity, [Fed Up] adopts a short-sighted, confrontational and misleading approach by cherry-picking facts to fit a narrative, [and] getting the facts wrong, and simply ignoring the progress that has been made over the last decade in providing families with healthier options at home and at school," Bailey said.

But despite the food industry's opposition to "Fed Up," the filmmakers and supporters aren't backing down. Couric has the food industry clearly in her sights. One of her hopes for the film, she said in a Q&A to promote "Fed Up," is to show Americans "how we are being brainwashed at an early age by the food industry, and the power of that lobby to prevent our legislators from making any meaningful changes."

"Fed Up" opens nationwide on Friday, May 9.