FORGET "WHERE'S THE BEEF?"—it's what's behind the beef that matters to Richard Linklater. The Austin, Texas–based director, who's spent his career alternating between edgy cult favorites (Dazed and Confused, A Scanner Darkly) and big-budget popcorn flicks (School of Rock, Bad News Bears), takes a bold leap into nutrition politics this month with Fast Food Nation, a fictional interpretation of Eric Schlosser's 2001 muckraking assault on pit-stop dining franchises. Linklater and Schlosser's collaborative screenplay used the research-rich book to conjure multiple narratives—a burger-chain executive (Greg Kinnear) sent to investigate rumors of feces in the meat supply, a Mexican illegal immigrant who's braved a border crossing for sweatshop shifts at a meat-processing plant, a fast-food clerk desperate to escape her greasy gig—interwoven to create an almost hopelessly grim and gruesome fable. The film boasts star power, with cameos by the likes of Ethan Hawke, Bruce Willis, and Patricia Arquette, and promises a shocking yuck quotient, thanks to a scene shot on the killing floor of a real slaughterhouse in northern Mexico. Steven Kotler grills the auteur about his last meal and America's coming diet war.

OUTSIDE: Your film focuses on everything you think is wrong with the fast-food industry. What's the one essential fix that needs to be made right now?
LINKLATER: God, there are so many. If the film awakens anything in anyone, I hope it's a general awareness of where fast food comes from and the true costs behind its production. Once you peek inside that world, it's fairly obvious—in terms of the animals, the environment, the sustainability, and the health of the individual consumer—that the system is broken. Sure, the end result is cheap and fast, but the production of it is anything but. There is no one fix. It's way too big for that.

So should we just scrap the whole industry and start over?
Fast food is a really efficient model, but the companies need to offer more healthy choices. Healthier drinks, healthier food, whole-wheat bread—just up the quality. I'll say this for the record: If McDonald's put a really healthy, decent-tasting veggie burger on their menu, I would drive through and buy one every now and then. And if five million other people agreed to do the same, we might actually see some change.

I take it you don't currently eat fast food.
Actually, I just had lunch at a place I consider fast food here in Austin called Mr. Natural. It's vegetarian Mexican food, cafeteria style. You go in and four minutes later you're eating.

Scenes from FAST FOOD NATION: Greg Kinnear at the fictional Mickeys burger franchise (Eric Lee/FOX Searchlight)