Former Iowa science teacher John Cisna, who says he lost 60 pounds on a six-month regimen of McDonald’s food and daily walks, has sparked outrage among public health advocates for taking his story to U.S. schools on the fast-food chain’s dime. Part of that challenge is winning over youngsters who have seen documentaries such as “Super Size Me” and “Fast Food Nation,” and as a result view McDonald’s food as a contributor to obesity, diabetes and other serious diseases. Cisna has tried to counter that impression, first with a book last year called “My McDonald’s Diet: How I lost 37 pounds in 90 days and became a viral media sensation,” detailing an experiment he said was created with his students.