Food, Inc. could have delivered a reach-for-the-Maalox montage of cows mired in manure, pig carcasses whacked about on conveyor belts and immobilized chickens locked in dark crowded coops to make its point about how mass food production has become such an unhealthy affair.

The film does dish up selected grotesque shots of slabs of beef, downer cows, dead hens and grimy CAFOs. There are a few gasp-aloud moments, such as when chickens are beheaded (inexplicably, the scene is chosen from footage of a sustainable farm operation — to show humane life and death?). But that aside, the beauty of this excellent documentary lies in its restraint. Rather than beating up corporate culprits Smithfield, Cargill and others with the big stick of blood and guts, Food Inc. confidently and methodically peels back the labels on our packaged food wonderland, telling an even-handed tale of relentless corruption and greed.

We begin in la-la land — a chilly grocery aisle where cheap subsidized corn infiltrates everything from mayonnaise to pancake syrup and the eerily perfect vegetables come engineered to survive shipping. The camera flows Lynch-like over beautifully arrayed aisles teeming with seeming variety, except that its an illusion. This bonanza of pre-fab food is composed mainly of subsidized commodities — corn and soybeans — and doused in cheap sweeteners like the high fructose corn syrup. A formula for poor nutrition, and diabetes.

Food, Inc. covers a lot of turf. It shows how we got here (agriculture that once nobly tried to pump up yields turned aggressive and restaurants adopted assembly line production — shout out to Mickey Ds!); how bad it is (cows fattened and sickened on grain that build up E. coli in their guts); how big it is (32,000 hogs killed every day at the world’s largest slaughterhouse in North Carolina), how warped (chickens bred to produce more breast meat pitch forward and can’t walk) and how negligent (as the system has grown, food inspectors have declined five-fold since 1970).

Pathogens, food poisoning victims, ineffective regulators, corrupt Washington influences. It’s all here, a feast of good intentions run amok and bad intentions covered up.

The film is relentless, and fascinating, as long as you’re not planning on dinner afterward. Reviewers have called it “riveting” and “horrifying”, (though I bet after a hiatus they’re still eating hamburger). To those familiar with the issues, it won’t be horrifying so much as a call to action. (You can answer that call on the website.)

Director Robert Kenner spent six years on this film, and it shows. Food, Inc. races back and forth between the producers and the consumers, but remains coherent. We get intimate glimpses of a financially strapped family shopping for groceries only to find that the hamburger is more affordable than the broccoli. There’s a classroom where the majority of kids raise their hands when asked if they have a family member with diabetes. A chicken producer reveals how the animals fare in a typical poultry house, risking her corporate contract (which she later loses). Diana De Gette remembers her toddler son, Kevin, poisoned by a hamburger infected with the E. coli bacteria.

The narrators, journalist and co-producer Eric Schlosser (Fast Food Nation) and author Michael Pollan, (Omnivore’s Dilemma), walk us through the complexities but don’t get in the way.