Natalie Portman On What Made Her Go From 'Vegetarian To A Vegan Activist'

Natalie Portman attends the Tribeca Film Festival 2009 portrait studio at DIRECTV Tribeca Press Center on April 23, 2009 in New York City Getty ImagesAccess Hollywood

LOS ANGELES, Calif. -- Natalie Portman is known for her vegetarian diet - but now, the star says, she's become not only vegan, but a an activist for the lifestyle.

"Some things are just wrong," she wrote in a Huffington Post editorial, citing author Jonathan Safran Foer's new nonfiction work, "Eating Animals," for convincing her to go vegan after 20 years as a vegetarian.

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"Perhaps others disagree with me that animals have personalities, but the highly documented torture of animals is unacceptable, and the human cost Foer describes in his book, of which I was previously unaware, is universally compelling," she wrote.

She went on to discuss the medical and bacterial issues - including the rise of swine flu - that Foer argues factory farming has contributed toward.

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"Foer details the copious amounts of pig s*** sprayed into the air that result in great spikes in human respiratory ailments, the development of new bacterial strains due to overuse of antibiotics on farmed animals, and the origins of the swine flu epidemic, whose story has gripped the nation, in factory farms," she wrote.

Natalie also revealed a personal anecdote from her college years at Harvard that helped inform her beliefs.

"I remember in college, a professor asked our class to consider what our grandchildren would look back on as being backward behavior or thinking in our generation, the way we are shocked by the kind of misogyny, racism, and sexism we know was commonplace in our grandparents' world," she wrote. "He urged us to use this principle to examine the behaviors in our lives and our societies that we should be a part of changing. Factory farming of animals will be one of the things we look back on as a relic of a less-evolved age."

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Natalie brought her non-meat-eating ways to "Top Chef" on Wednesday night, surprising contestants preparing to cook up an animal-centric meal in Tom Colicchio's Craftsteak restaurant. Though she's serious about her food, the star offered a lighthearted presence at the judge's table, telling contestant Michael Voltaggio that his banana polenta and asparagus salad "makes me smile and laugh, and I'm confused!"

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