BRAD BLANTON, FOUNDER of a movement called Radical Honesty, is swirling a glass of bourbon and water as he sits by a fire in his rural Virginia home, telling me why it’s important to live without lies. “You’ll have really bad times, you’ll have really great times,” he says, “but you’ll contribute to other people because you haven’t been dancing on eggshells your whole f---ing life.”

Radical Honesty is based on a simple premise. Blanton, a 69-year-old psychotherapist, claims that everyone would be happier if we just stopped lying, if we just told the truth, all the time. That would be radical in itself, of course—a world without fibs. But Blanton goes further. He says we should toss out all the filters between our brains and our mouths. If you think it, say it. Confess to your boss your secret plans to start your own company. If you’re having fantasies about your wife’s sister, Blanton says to tell your wife and tell her sister. To him, it’s the only path to authentic relationships, the only way to smash through modernity’s soul-deadening alienation. Oversharing? No such thing.

Yes. I know. One of the most idiotic ideas ever: Deceit makes our world go round. Without lies, marriages would crumble, workers would be fired, egos would be shattered, governments would collapse.

And yet … maybe there’s something to it. Maybe a couple of weeks of truth-telling would do me good. When I e-mailed Blanton to ask if I could come down to Virginia to get a few pointers, he wrote back: “I hope you’re not just doing a cutesy little superficial dipsh-- job like most journalists.

BLANTON, IN PERSON, isn’t the bully I expect. He’s a former Texan with a big laugh and a big voice. He calls himself “white trash with a Ph.D.” Twice he’s run for Congress, on the novel platform that he’d be an honest politician. In 2004, he ran as an independent and won a surprising 25 percent of the vote in his Virginia district. In 2006, Democrats considered endorsing him but got skittish about his weeklong workshops, which involve a day of total nudity.

My interview with him turns out to be unlike any other in my years as a journalist. Usually, there’s a fair amount of butt kissing and diplomacy. But with Blanton, I can say anything that pops into my mind. In fact, it would be rude not to say it. I’d be insulting his life’s work.

“I was disappointed when I visited your office,” I tell him. (Earlier, he had shown me a small, cluttered single-room office that serves as the Radical Honesty headquarters.) “For my essay, I want this to be a legitimate movement, not a fringe movement.”

“What about a legitimate fringe movement?” he says.

Blanton’s movement is at least sizable, if not huge. He has sold 175,000 books in 11 languages and has 25 trainers assisting workshops and running practice groups around the country.

I practice too. When he veers too far into therapyspeak, I say, “That just sounds like gobbledygook.” “Thanks,” he replies. “That’s fine.”

“Do you think it’s ever okay to lie?” I ask.

“I advocate never lying in personal relationships. But if you have Anne Frank in your attic and a Nazi knocks on the door, lie. I lie to any government official. I lie to the IRS. I always take more deductions than are justified.”

“I’m glad you picked your nose just now,” I say. “Because it was funny and disgusting, and it’ll make a good detail for the piece.”

“That’s fine,” he says again. “I’ll pick my ass in a minute.” Then he unleashes a deep Texan laugh: heh, heh, heh.

UPON MY RETURN to New York, I immediately set about delaying my experiment. When you’re with Blanton, you think, Yes, I can do this! The truth, the whole truth, nothing but the truth. But when I get back to bosses and fragile friendships, I continue my lying ways.

“How’s Radical Honesty going?” my boss asks. “It’s okay,” I lie. In fact, not until my boss says he needs the story ASAP do I get serious about the project.

I start in at dinner with my friend Brian. We are talking about his new living situation, and I decide to tell him the truth: “You know, I forget your fiancée’s name.” (This is highly unacceptable—they’ve been together for years; I’ve met her several times.) “It’s Jenny,” Brian says.

In his book, Blanton talks about the thrill of total candor, the Space Mountain–worthy adrenaline rush you get from breaking taboos. As he writes, “You learn to like the excitement of mild, ongoing risk-taking.” This I feel.

Luckily, Brian doesn’t seem too upset. So I decide to push my luck. “Yes, that’s right. Jenny. Well, I resent you for not inviting me to your and Jenny’s wedding. I don’t want to go, since it’s in Vermont, but I wanted to be invited.” “Well, I resent you for not being invited to your wedding.” “You weren’t invited? Really? I thought I had.” “Nope.” “Sorry, man. That was a mistake.”

A breakthrough! We are communicating! Blanton is right. I’m enjoying this. A little bracing honesty can be a mood booster.

The next day, my wife, Julie, and I get a visit from Julie’s dad and stepmom.

“Did you get the birthday gift I sent you? Did you like it?” asks her stepmom. “Not really. I don’t like gift certificates,” I say. “It’s like you’re giving me an errand to run.” Once again, I feel the thrill of inappropriate candor. And I feel something else, too. The paradoxical joy of being free from choice. I had no choice but to tell the truth. I didn’t have to rack my brain figuring out how to hedge it, spin it, massage it. “Just being honest.” I shrug. Nice touch, I decide; helps take the edge off. She’s got thick skin. She’ll be okay. And I’ll tell you this: I’ll never get a damn gift certificate from her again.

By the end of the week, I’ve slashed my routine lying by at least 40 percent.

One thing becomes quickly apparent, though: There’s a fine line between Radical Honesty and creepiness. It’s simple logic: Men think about sex every three minutes, as the scientists at Redbook remind us. If you speak whatever’s on your mind, you’ll be talking about sex every three minutes.

I have a business breakfast with an editor from Rachael Ray’s magazine. As we’re sitting together, I tell her that I remember what she wore the first time we met and that I’d try to sleep with her if I were single. I even confess to her that I just attempted (unsuccessfully) to look down her shirt during breakfast.

She smiles. Though I do notice she leans back farther in her seat.

The thing is, the separate cubbyholes of my personality are merging. Usually, there’s a professional self, a home self, a friend self, a with-the-guys self. Now it’s one big improper mess. Either this woman and I have taken a step forward in our relationship, or she’ll never return my calls again.

When I get home, I keep the momentum going. I inform our nanny, Michelle, that “if my wife left me, I would ask you out on a date, because I think you are stunning.” She laughs. Nervously. “I won’t mention it again,” I say. Now I’ve made my own skin crawl. But I carry on.

While getting my hair cut, I stop my barber short when he starts telling me how he doesn’t want his wife to get pregnant. “You know, I’m tired. I have a cold. I don’t want to talk anymore. I want to read.” “Okay,” he says, wielding his scissors, “go ahead and read.” Later, I do the same thing with my in-laws when they’re yapping on about preschools. “I’m bored,” I announce. “I’ll be back later.” And with that, I leave the living room.

Radical Honesty can save a whole lot of time.

MY BREAK WITH Blanton’s philosophy comes soon enough. A friend of a friend wrote some poems and sent them to me. This was an older man. His wife had just died, and he’d taken up poetry. He just wanted someone “in publishing” to read his work, and though I didn’t like the poems much, I wrote to him that I thought they were very good.

I confess my lie in an e-mail to Blanton, then ask if I made a mistake. Blanton responds curtly, advising me to “send the man the e-mail you sent me and ask him to call you when he gets it.

Show him the e-mail? Is he kidding? In his book Radical Honesty, Blanton advises us to start sentences with the words “I resent you for” or “I appreciate you for.” So I write back to him: “I resent you for giving me the advice to break that old man’s heart.

Blanton responds quickly. First, he doesn’t like that I expressed my resentment by e-mail. He expects resentment to be expressed in person so that “you can stay with” the person you resent “until the sensations arise and recede and then get back to neutral—which is what forgiveness is.” Second, he tells me that telling the old man the truth would be compassionate. “Your lie is not useful to him. In fact, it is simply avoiding your responsibility as one human being to another.

I try to understand Blanton’s point about compassion, and I will concede that my e-mail to the old man was wrong. I shouldn’t have been so rah-rah effusive. But I’ve hit the outer limit of Radical Honesty, a hard wall. I can’t trash the old man.

I call Blanton several days later to tell him I intend to end my experiment. “You’re going to start lying again?” he asks. “Hell, yeah,” I say, then concede, “But I’m going to lie less than I did before.”

I can say this for Radical Honesty. Whenever I am radically honest, people become radically honest themselves. In fact, all my relationships could take a whole lot more truth than I expected.

But the giddiness I experienced at first wore off pretty quickly. A life of Radical Honesty is filled with a hundred confrontations every day. They’re small, but relentless. “Yes, I’ll come to your office, but I resent you for making me travel.” “My boss said I should invite you to this meeting, although it wouldn’t have occurred to me to do so.” At one point, my wife told me a story about switching operating systems on her computer. In the middle, I had to go help our son with something, then forgot to come back. “Do you want to hear the end of the story or not?” Julie asked. “Well … is there a payoff?” I asked.

“F--- you.”

“That’s good,” Blanton says to me when he hears the story. “I like that. That’s communicating.”

Adapted from the book The Guinea Pig Diaries by A.J. Jacobs. ©2009 by A.J. Jacobs. Used with permission of Simon & Schuster, Inc.