As filmmaker Morgan Spurlock points out, it's every kid's dream: Eat nothing but McDonald's for 30 days. But it turned into a nightmare. By the end of Spurlock's cross-country fast-food odyssey, he'd put on 25 pounds, his cholesterol had skyrocketed, his liver was in jeopardy and doctors were begging him to stop. All thanks, he asserts, to his new diet — and not exercising at all. The whole ordeal, interwoven with an exploration of America's weight problem, is captured in the award-winning documentary Super Size Me, in theaters now.

Q: So what's your movie really about?

A: Super Size Me is a look at fast food and obesity in America. A lot of people think I'm attacking McDonald's, but I didn't come into this to attack McDonald's; I came into this to attack the American way of life, which has become a real fast-food culture. It's like Eric Schlosser's book [Fast Food Nation, Perennial, 2002] — we've become a fast-food nation, where this type of food has influenced everything, from the way we live to the way we eat to how other foods are made to school lunches, so I wanted to explore that. It's a huge problem that has so many facets, it was even difficult to get what we had in the movie.

Q: What did you think would happen on the diet?

A: I figured I'd gain some weight. I was putting my faith in [three different] doctors that nothing bad was gonna happen. And in the beginning they were like, 'Yeah, your cholesterol may go up a little bit, you may gain 10 pounds, but that's it.' And so when everything kinda starts to fall apart in the movie, it was very scary.

Q: Was there any point where you were like, 'Screw this'?

A: On Day 21, when the doctors told me to stop, right now. I called everybody [for advice]. And then my oldest brother said, 'Morgan, people eat this s–t their whole lives. You think it's gonna kill you in nine days?' And I said, 'You're exactly right … I'm gonna keep going.'

Q: Beyond the physical effects, what else surprised you?

A: School-lunch programs are shocking. And parents don't know. They're trusting that the school is doing what's right for their kids, and they're not. They're serving garbage.

And now we're getting rid of health classes, phys-ed classes [and] recess in a lot of schools. It's just unbelievable.

We also went to hospitals that have fast-food places. And you ask the doctors, 'How the f–k can you have this food in here, in a place of healing?' And they're like, 'Well, we have kids here who have cancer, and this is the only thing they'll eat.' And I'm like, 'Why don't you just give them some poison while you're at it?' It's like Flowers in the Attic. 'Here's a cookie with arsenic in it — have a good time.'

Q: Why'd you pick McDonald's?

A: It's the biggest food corporation in the world. And it has influenced the way the whole business works; everyone follows it.

Q: What would you like to see fast-food companies do?

A: Have more healthy options. Put the calories up on the board, just so people know. Get rid of supersize portions. Get rid of the 42-ounce Coke. That's ridiculous. Who needs 31/2 cans of Coke? Nobody.

Q: Is there anything these companies do well?

A: They market really well.

Q: So what can consumers do?

A: People need to realize that every time you go out to eat, you're voting with your fork. "Here's what I believe in, here's what I stand for." And if people continue to say, "I believe in this, I support this," then they're gonna keep making it … McDonald's says its food can be part of a balanced diet. That's true, so long as everything else you eat is actually real food. Because this isn't real food at all. It's been so processed and treated and preserved — it's been taken so far away from any food source that the nutrients are gone.

Q: Have you been to McDonald's since you made the film?

A: No.

Q: Are you ever going back? Will there be wanted posters of you on the walls?

A: Yeah, and clowns with shotguns outside. In the film, nutritionists say you shouldn't eat this food more than once a month. So, according to that, I ate more McDonald's than you should in eight years. So maybe in eight years, I'll think about going back. You can never say never. — Steve Mazzucchi

Note: Six weeks after Super Size Me's Sundance premiere, McDonald's announced it would phase out super-sizing by the end of 2004. A company spokesman insisted there was no connection. For more on the movie, visit supersizeme.com