As the American school curriculum gets an overhaul, here's another area administrators should be paying attention to: how to manage a controversy.

An Iowa science teacher named John Cisna has sparked criticism for taking his message about his "McDonald's Diet" into about 90 high schools and colleges, with critics saying the program is little more than corporate branding for a fast-food giant. Cisna is a "brand ambassador" for McDonald's (MCD), which is paying for his time and travel, according to a spokeswoman for the fast-food giant.

Cisna, 56, joined the lecture circuit after devising a plan to lose weight by, according to his Facebook page, "eating nothing but McDonald's for breakfast, lunch and dinner for 90 days straight." His message: Americans can "lose weight while still eating the foods you love, like Big Macs and Hot Fudge Sundaes."

He adds, "It's not the fast food companies making people fat."

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That message clearly struck a chord with McDonald's, which said it pays for Cisna's time and travel as well as supporting his "desire as a teacher to provide students with facts to make informed choices."

But regardless of whether one thinks it's advisable to turn to fast food as a weight-loss technique, critics argue that Cisna's talk has no place in public schools, given that he's backed by a corporation that has a history of targeting children with marketing messages.

"At the end of the day, our schools should not be places where corporations market their brands to children, and particularly not McDonald's, given its role in driving an epidemic of obesity," said Sriram Madhusoodanan, an organizer at Corporate Accountability International, a Boston-based nonprofit.

In an interview, Cisna said his message isn't about McDonald's specifically. The point of his talk, he said, is that he wants children to understand it's not where you eat, but how much you eat that leads to obesity. He noted that he started off at 280 pounds and was "really fat" after eating home-cooked dishes and food at sit-down restaurants. His weight-loss experiment revolved around eating a daily 2,000 calorie diet at McDonald's, which he says shows "there's no such thing as bad food."

"Every time we go to throw fast food under the bus, it enables me," he said. "Let's quit blaming other things for obesity."

Not everyone is buying Cisna's message. In the view of Corporate Accountability International, which has campaigned against the tobacco, bottled water and fast-food industries, Cisna's talk is "absolutely subversive," Madhusoodanan added. "At the end of the day, this is one big informercial for McDonald's masquerading as education."

Part of Cisna's message is told through a film called "540 Meals: Choices Make the Difference," which documents his experiment. According to the blog The Lunch Tray, Cisna wanted to "discredit 'Super Size Me.'" That refers to the 2004 film by documentarian Morgan Spurlock, in which he ate only McDonald's food. Far from losing weight, Spurlock gained 24 pounds.

Cisna said "Super Size Me" was one influence on his decision to try dieting at McDonald's. "I thought, 'What is the educational value to show a man who eats uncontrollable amounts of food, stops exercising and gains weight? What is the value in that?'"

Spurlock, by the way, appears to view Cisna with the same level of antipathy, writing on Twitter on Thursday about Cisna's school talks: "Dear @McDonalds - thx for continuing to remind the Earth how terrible you are."

McDonald's has made a point of targeting schools as a way to boost its brand, which is under pressure from food activists who say it contributes to America's obesity epidemic. Americans have in recent years increasingly choosing restaurants offering fresher food, such as Chipotle (CMG) and Panera (PNRA), which rely on organic or ethically harvested food for some dishes.

Late last year, a McDonald's executive said the company would refocus on marketing to children and families because of a severe sales slump. Part of that plan involves sponsoring kids' sports teams and McTeacher Nights, when teachers work at a McDonald's location for free, with the restaurant giving 20 percent of the profits to the teachers.

Cisna said schools aren't canceling his appearances as a result of the controversy. Asked if he would consider halting his funding from McDonald's as a way to avoid the appearance of marketing, he said he "can't fathom" why people believe it's problematic. He added that he couldn't afford to travel to schools without that support.