Frank R. Reese Jr. is the proprietor of Good Shepherd Poultry Ranch, where he raises chickens and turkeys humanely. (Sundance Selects)

Rating: 3 stars

There are many disturbing phrases bandied about in “Eating Animals,” the Natalie Portman-narrated documentary about the morality of meat-eating, based on the 2009 nonfiction bestseller by Jonathan Safran Foer. Some involve wonk-speak, such as “CAFO,” an acronym for “concentrated animal feeding operation.” (The name itself is less upsetting than the inhumane reality.) Other terms, such as “fecal marinade” — a reference to what one interview subject calls the ­Pepto-Bismol-pink “hog lagoons” that dot the countryside where pork is produced, and where lakes of animal waste bake in the sun — are simply disgusting.

That visceral reaction, I suspect, will not be an uncommon one to this provocative — and ultimately persuasive — film, which aims to make viewers re-evaluate their relationship to carnivorism not merely by shocking, but also by positing that there may be an ethical middle ground between vegan abolitionism and the mindless scarfing-down of burgers from factory-farmed cows.

Reading sometimes-portentous texts taken from Foer’s book, Portman, a vegan, is the main tour guide on this challenging excursion to the world of slaughterhouses and CAFOs, which one commentator likens to petri dishes for antibiotic-resistant bacteria. But it’s wordsmiths like that commentator and others throughout the film (such as veterinarian and animal-welfare whistleblower Jim Keen, who once worked at the U.S. Meat Animal Research Center) who make the film’s strongest and most eloquent points.

At once a history and critique of American farming, as well as a philosophical examination of the potential for human kindness to trump our love of bacon, “Eating Animals,” at its core, poses two hard questions, the latter of which might seem intractable: “How did we get here?” and “How do we go somewhere else?”

If you’re a barbecue lover with the stomach to see it, “Eating Animals” may not stop you from ordering the house special. But it could cause you to think twice about where those chicken wings — and those ribs, that brisket — came from.

Unrated. At Landmark’s E Street and Bethesda Row cinemas. Contains brief strong language and disturbing images of slaughterhouses and suffering animals. 94 minutes.