America, birthplace of the Big Mac, is the fattest country in the world, and continues to engorge at an artery-clogging rate. Thirty percent of Americans are obese, a staggering figure, especially when put into context of a public health crisis: Obesity is the second leading cause of preventable disease in America, number one being smoking. It is already an enormous burden on Medicare and other public health programs.

Are fast-food companies to blame for our poor health, and if so, where does individual responsibility end and corporate responsibility begin in a country that is plastered top to rotund bottom in advertising for lethally unhealthy food? To tackle this question face first, Super Size Me director/subject Morgan Spurlock ate nothing but McDonald's food for an entire month, three times a day, in order to study the diet's effect on the body. The premise behind this excellent and engaging documentary is a child's dream come true--and that, contends the roster of nutritionists and public advocates interviewed in the film, is precisely the problem. This year's winner for best documentary direction at Sundance, Super Size Me unleashes an attack against the marketing tactics of fast-food companies and the lobbies that support them, all the while offering ample scientific proof of why one should never, ever, eat a McNugget again.

The film follows the director for a month as he travels across America, eating quarter-pounders and interviewing lawyers, doctors, dieticians, school lunch providers, Surgeon Generals, and anyone else who plays a part in the developing battle between Big Food and public health. Before beginning the diet, Spurlock hires a team of physicians to monitor him over the course of the month, who assess that he is above average in overall health and fitness. Each of the three guesses that his cholesterol and triglyceride levels will probably go up by the end of the month, but little else. That said, it's a genuine shock to Spurlock and his doctors how quickly and completely his health deteriorates. None of them is prepared for the extent of the physical damage, and by the end of the third week, they beg him to quit the diet and return to a normal eating routine, fearing irreparable changes to his health. He gains 30 pounds, his cholesterol shoots up 65 points, and his liver is in toxic shock, well on the road to total failure. This is to say nothing of the side affects of the diet, which include mood swings, cravings, loss of sexual appetite, and chest pains.

Of course, no one in his right mind would voluntarily maintain the kind of diet that the director suffers through for a month. Nor does McDonald's advocate it. In fact, in press releases invoked by a lawsuit, McDonald's states that the detrimental effects of their food are "common knowledge," and that it is equally well-known that processed food has much less nutritional value than fresh food--comments like this from corporate spokespeople pepper the film, and insinuate an awe-inspiring degree of negligence on the part of fast-food companies. Still, an incredible number of people eat their food every day (in studies, we are told, McDonald's refers to these customers as "heavy users" and "super heavy users"), and food of comparable quality is served in school lunch programs virtually everywhere. And junk food is chemically and psychologically addictive; between sugar crashes and wild burger cravings that literally wake him up in the middle of the night, Spurlock interviews a doctor who attests to the opiate-like powers of fat and sugar in foods like chocolate and french fries. Sure, the director may be acting "irresponsibly," to quote a spokesman for McDonald's, but during his brief jaunt across America, Spurlock interviews a man who drinks so much diet soda, up to eight liters a day (!), that he once went blind for a week from late-onset diabetes. Another man's solid diet is comprised almost exclusively of Big Mac sandwiches. These are not masochists or martyrs or just plain idiots, the film argues, but sane inhabitants of an American landscape in which the omnipresence of advertising and the verifiably addictive qualities of junk foods are causing a very serious and totally preventable epidemic.

In the film's conclusion, the diplomatic Spurlock maintains that he doesn't mean to single out McDonald's as the enemy of public health, but has chosen the Golden Arches because of its statistical domination in the field of fast food and because of its iconic stature in the American mythos. The purpose of the film, he says, is to make people more aware of the foods they eat, and the possible repercussions they are risking. To this end, Spurlock's project is successful, and the ensuing question will be of great importance in coming years: Shouldn't companies that reap profits from the dietary habits of the public they've seduced at least try to do their part to make this a healthier country?

--Gabriel Cohen DeVries