Why is a former teacher promoting his 'McDonald's diet' to students?

John Cisna, a science teacher from Iowa, was upset by the documentary "Super Size Me," in which a man ate only McDonald's food and gained weight and a host of health problems.

The experiment wasn't very good science, and unfairly tarnished fast food companies, said Mr. Cisna, so he decided to do something about it. The 280-pound teacher embarked on a plan to eat only food from McDonald's for six months, limiting himself to 2,000 calories a day and exercising regularly. The results were eye-opening: After six months on his "McDonald's diet," in which he ate every item on the fast food chain's menu at least once, Cisna lost 56 pounds, dropped four waist sizes, and even lowered his cholesterol by a third.

He wrote a book and produced a video about his experience, and was promptly hired by McDonald's as a brand ambassador. He has told his story at more than 90 colleges and high schools across the country, with McDonald's footing the bill.

"I'm not endorsing fast foods,'' Cisna told NBC's Today show Tuesday. "I'm endorsing that kids need to start using critical thinking skills when it comes to making the right choices of what they eat."

The new program, especially Cisna's touring of schools, has sparked intense criticism.

"On one hand, it's a fairly transparent, pathetic effort to undo lingering brand harm from 'Super Size Me,'" Robert Weissman, president of Commercial Alert, a group dedicated to "keeping commercial culture within its proper sphere," told The Christian Science Monitor in an interview. "On the other, it's an outrageously devious scheme to insert McDonald's advertising into school curricula."

A Change.org petition to "keep McDonald's infomercials out of schools" has received nearly 60,000 signatures, and advocates speaking out against the new program include nutrition expert Marion Nestle and corporate accountability organizer Sriram Madhusoodanan.

"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," Mr. Madhusoodanan told CBS News. "At the end of the day, this is one big infomercial for McDonald's masquerading as education."

McDonald's says the program is not about its brand, but about making quality food choices anywhere.

"John’s story is not a weight loss plan, and we do not recommend that anyone eat every meal at one restaurant every day for an extended period," McDonald’s spokeswoman Lisa McComb told Fortune. "Rather, John’s story is about making informed and balanced choices no matter where you choose to eat and incorporating exercise into your daily routine."

Mr. Weissman dismisses those claims.

"When McDonald's is purportedly advancing a message about healthy choices with a spokesman whose plan involves eating every meal at McDonald's, come on, that does not pass the laugh test," he says.

Critics point to McDonald's struggling US sales and the chain's long-standing strategy of reaching out to children, families, and schools.

While the fast food giant has a history of providing financial support to educators and parent-teacher groups, late last year a McDonald's executive announced a refocus on marketing to children and families. The new kid-forward campaign involves sponsoring kids' sports teams and McTeacher Nights, in which teachers work at a McDonald's restaurant for free, in exchange for 20 percent of the profits from their shift going to teachers, according to reports.

These programs, along with the new school touring campaign, are part of McDonald's longstanding history of marketing to children, says Weissman.

"McDonald's has always targeted children, that's why they have playgrounds inside the restaurants," he says. "School marketing schemes are about bringing children into McDonald's, and finding ways to make them regular McDonald's customers. Additionally, they're about building the McDonald's brand identity and making McDonald's seem as an integral part of the community, a local institution, not a giant multinational."

He added, "These programs are definitely a way to try to rehabilitate the brand."