Two weeks ago, I flew to a film festival in Austin, Texas, to watch what could be one of America's hottest movies this spring: an engaging documentary called "Super Size Me," which shows what happens when you stuff yourself for a month and don't exercise.

The creator and star, Morgan Spurlock, won best director honors at Sundance, and Roger Ebert and Richard Roeper have given the movie two thumbs up. It won't reach theaters until May 7, but the word of mouth is already deafening.

Here's the premise: Spurlock eats at only McDonald's and stays sedentary for 30 days. He gains 24 pounds, his cholesterol rises 40 percent, he feels lousy and his sex life collapses.

The movie is certainly timely. The Centers for Disease Control and Prevention just reported that the No. 2 cause of death in the United States after smoking is "poor diet and physical inactivity."

But "Super Size Me" is not a serious look at a real health problem. It is an outrageously dishonest and dangerous piece of self-promotion. Through his antics, Spurlock sends precisely the wrong message. He absolves us of responsibility for our own fitness. We aren't to blame for being fat; big corporations are. And the remedy, he suggests, is to file lawsuits and plead with the Nanny State and the Food Police for protection.

While the film demonizes McDonald's and other restaurants, Spurlock's weight gain and health decline have nothing to do with where he ate, but rather with how much he consumed and how little he exercised. He even cut down on normal walking.

It's no accident that Spurlock's production company is called "The Con." A prankster from way back, he briefly ran a program on MTV called "I Bet You Will," where he paid people to do disgusting things.

A woman shaved her head, combined the clippings with butter to form a gigantic hairball and then ate it -- for $250.

Sorry for the unappetizing detail, but it tells who Morgan Spurlock really is. He presents himself as a socially concerned artist, but, in fact, he is up to his old tricks.

The math of weight gain is simple. Someone Spurlock's size can eat 2,500 to 3,000 calories a day and maintain his weight. In the movie, he eats 5,000 to 5,500 calories a day. Nutritionists calculate that a man gains roughly a pound for every 3,500 extra calories. So roughly every three days, Spurlock overeats his way to an extra two pounds or more.

He could have gained that extra weight anywhere and he could have burned off the extra weight had he exercised. Then he whines that it's all Ronald McDonald's fault.

In fact, it's not easy to eat 5,000 calories at McDonald's.

Consider this daily diet: a breakfast of Egg McMuffin, orange juice and coffee; a lunch of Big Mac, medium fries, Coke and hot caramel sundae; and a dinner of 10 chicken McNuggets, sweet and sour sauce, milk and Fruit 'N Yogurt Parfait. Total calories, according to the McDonald's Web site: 2,730. What Americans need is balance: sensible eating plus exercise. Staying fit is a matter of personal choice and responsibility -- which are just what this con man and his co-conspirators want to take away from you.