"Super Size Me," a funny but tendentious film that ends with a wishful image of Ronald McDonald's grave, begins with an epigram from McDonald's founder Ray Kroc: "Look after the customer, and the business will take care of itself." It's not clear whether Morgan Spurlock, the film's director and star, is mocking Kroc or suggesting that his corporate descendants have forsaken his credo.

 Perhaps that's because Spurlock can't quite decide. He seems torn between the main story line of his movie, in which sneaky corporations manipulate people into overeating, and the more complicated reality, in which companies respond to consumer demands that are only sometimes driven by health considerations.

 "For me," Spurlock announced at the Washington, D.C., International Film Festival on May 2, "the personal responsibility issue is very important." Yet the movie, which opened nationwide on Friday (May 7) (and in which I briefly appear), presents the results of Spurlock's month-long McDonald's binge as validation of the reasoning behind the unsuccessful lawsuit that two obese New York City teenagers filed against McDonald's in 2002.

 Spurlock says his exercise in extreme eating, during which he gained nearly 25 pounds, was aimed at determining whether fast food is "unreasonably dangerous," which would make it "defective" under product liability law, and whether it causes "injury," which plaintiffs must demonstrate to recover damages. But in planning his fast-food feat, he paid no heed to the central reason the McDonald's lawsuit was dismissed.

 In his January 2003 ruling, U.S. District Judge Robert Sweet declared that "any liability based on over-consumption is doomed if the consequences of such over-consumption are common knowledge." He continued: "If a person knows or should know that eating copious orders of supersized McDonald's products is unhealthy and may result in weight gain . . . it is not the place of the law to protect them from their own excesses. Nobody is forced to eat at McDonald's. . . . Even more pertinent, nobody is forced to supersize their meal or choose less healthy options on the menu."

 Although Spurlock concedes "my experiment may have been a little extreme," he notes that some people do eat at McDonald's regularly, even daily. But despite the plethora of calorie-packed dishes offered by McDonald's, he easily could have eaten three meals a day there without gaining weight.

 For instance, an Egg McMuffin, orange juice and coffee for breakfast; a grilled chicken bacon ranch salad and iced tea for lunch; and a double cheeseburger, medium fries and diet Coke for dinner total fewer than 1,800 calories, well under the 2,500 Spurlock's doctor says he needed to maintain his starting weight of 185 pounds. By contrast, Spurlock says he consumed some 5,000 calories a day, while deliberately avoiding physical activity.

 In short, Spurlock's "experiment" proves nothing but basic physics. Still, he is right in suggesting there's an association between the proliferation of restaurants and Americans' bulging bellies. That impression was confirmed by a statistical analysis the National Bureau of Economic Research published in October 2002. Continued...