When I first saw the trailer for Food, Inc. I could tell immediately that the film would address vital and disturbing developments in the way our food is processed, distributed and legislated. But I was afraid the facts would get lost in polemic, that the movie would be shrill and smug. I was wrong.

Food, Inc. is full of alarming information, but it is not alarmist. I jokingly called it a vegan horror movie not long after the credits rolled, but the revelations within are terrifying for everyone. Yes, this is a horror movie, and all the more frightening because it is calm, reasoned and, in many cases, quite right. You’re not likely to see another film this year that has this power to change your thinking and habits.

The goal of director Robert Kenner is simple: look behind the veil of America’s industrialized food industry. No one should have to eat at a restaurant where you couldn’t look into the kitchen. Yet we feed daily on processed plant and animal products whose origins are guarded to the point of military secrecy. Chickens are grown in dark coops, never seeing sunlight; animals are unable to walk as their genetically modified muscle mass develops out of sync with their organs and skeletal systems. ‘Farmers’ are often prodded into indentured servitude to raise animals in ways they’re not allowed to disclose.

Kenner paints a simple timeline in which the emphasis on corn farming has provided the backbone of the corporate food industry, decimated Mexican corn farming in conjunction with NAFTA and helped to push immigrants north to work illegally in increasingly dangerous meat processing plants (already reformed and made honorable a century ago before being allowed to slip back into unregulated horror) while CAFOs (concentrated animal feeding operations) house corn-fed cows that wallow in their own filth and grow guts full of e-coli that wouldn’t naturally occur on a grass diet.

That’s just a segment of the film. This movie is dense with information and rarely bothers to be sentimental. Quite a lot of the facts within will be familiar to the converted, so there is as much effort given over to presentation as research; this is a compulsively watchable and engaging movie. Rather than leaving off a creating a clever powerpoint presentation of familiar info, Kenner looks forward as questions of health point toward a massive collection of social issues.

Why is a double cheeseburger from McDonald’s cheaper than a head of iceberg lettuce? How is illegal immigrant labor part of the industrial supply chain, and what are the most evident ways workers are exploited? When a company cares as little about the health and sustainability of a product as Tyson seems to care about chickens and Smithfield Farms does about livestock, how can they possibly extend better care to their workers and, eventually, their customers?

The film is not dour, nor is it convinced that this is a permanent state of affairs. Quite the opposite. The qualities that makes the documentary so appealing are hope and understanding. Arguably, the conclusion that consumers hold the ultimate power to change affairs is difficult to believe. Large groups have spent no small amount of time attempting to reform our food industries. Yet big tobacco was brought in line — could the same policy change eventually re-regulate meat production?

For some input, Kenner turns to the same spokesman Michael Pollan did in his book The Omnivore’s Dilemma: Joel Salatin of Polyface Farms. Salatin is a born showman, engaging and funny. It’s difficult not to believe him. But Polyface is the real deal, a three-generation farm that is one of the healthiest, most natural operations in the country.

Through Salatin’s example, and the cool reason of Pollan and Fast Food Nation author Eric Schlosser, Food, Inc. is able to depict policies and corporate behavior that are shocking even in our monopoly-happy time, and still end on an inspirational note. As entertaining as it is provocative, Food, Inc. may be the most important movie you’ll be riveted to this year.

8.9 out of 10

This review is based on a public screening of the film at the Independent Film Festival Boston. Read more about the issues raised in Food, Inc. at TakePart.com. Below, Robert Kenner speaks about the film in a Q&A from AFI Dallas.