THIS MORNING, MIKE TYSON AROSE AT 8 A.M. and had his customary breakfast: oatmeal, Cheerios, almond milk. Last night, he had his usual dinner: spinach, broccoli, rice. “Before I was a vegan, I ate garbage,” he says, sitting in a hotel room in downtown Manhattan, shaking his head. “After a fight, I’d eat like a pig: splits, doughnuts, steak, toxins, poison, anything, grab it.” Tyson is in New York for his one-man Broadway show, The Undisputed Truth: a captivating, off-kilter chronicle of a life spent trying – and, more often than not, spectacularly failing – to keep his outsize appetites in check. “I’m a gorger,” he says.

Wearing jeans and a light-blue T-shirt, Tyson rubs his biceps softly, looking as beatific as a man with a tribal-warrior tattoo covering half his face can look. But even discussing veganism, Tyson can show glints of the volatility that made this former Brownsville, Brooklyn, stickup kid such a ferocious fighter. “You hear from some people – what do they call it? Rabbit food? Fag food?” he says. For a moment, his eyes go blank. “I will kick somebody’s ass if they keep talking some ‘fag food’ shit.”

Many somebodies get their asses kicked in The Undisputed Truth, which began life last spring as a glitzy Vegas production before Spike Lee signed on to direct a stripped-down New York version. “When it comes to talking about himself, Mike’s the most honest person I’ve ever met,” says Lee. “Highs, lows – he doesn’t care.” Over two hours, Tyson works a bare stage in a dark suit, reminiscing about his youth, his divorce from Robin Givens, his 1992 rape conviction, his cocaine addiction and the countless beat-downs he administered inside the ring and out. Tyson characterizes himself as a natural raconteur with eons of crazy tales to share: “People come over, I tell stories about what I know, what I’ve learned.”

Onstage, Tyson bellows, “I love me some cocaine!” So is he afraid of backsliding? “Any moment – it’s always a struggle,” he says. “When I f*** up, I really f*** up. Anything could trigger it: the sound of a Marlboro Red lighting up, because I’d smoke cocaine in Marlboros.”

While in New York, Tyson has been traveling to Brooklyn, where he still houses- trained pigeons in Bushwick. “I go a couple times a week,” he says tenderly. The whiplash extremes of Tyson’s gentleness and viciousness animate the show, which swerves from gross-out comedy to somber tear-jerker mode without warning. Nowhere is Tyson more pained than when discussing his children. “I wasn’t the greatest father,” he tells me, noting that he’s been known to text his kids and make surprising, hurtful errors: “They go, ‘Dad, that’s not how you spell my name!’ I’m like, ‘F***, these are college-educated kids, and I’m a dumb f***ing nigger.’”

After New York, the show will travel the world, Tyson says: “Singapore, England, Australia, New Zealand, I think South Africa.” He’s already plotting ways to up his showmanship. “It may seem weird or wimpy,” he says, “but I want to have some quick dance acts in there. I’d love to sing, but I can’t. Maybe I’ll get the guts one day.”