Yuan-tsung Chen, an author, leaned forward in an oversize velvet chair to tell the story of the man so hungry that he ate himself.

Once, that tale had seemed unbelievable to her. “I thought that was an exaggeration,” she said. But living in a village during the Great Leap Forward, Mao Zedong’s calamitous attempt to catapult China into communist plenty in the late 1950s, changed her view on what extreme hunger could drive people to actually do.

“It wasn’t anyone’s exaggeration, it was as true as real life, but nobody would say it,” Ms. Chen said, recalling the desperation and starvation caused by Mao’s experiment. Historians estimate that up to 45 million people died over the course of five years.

Now, sitting at a restaurant in one of Hong Kong’s most opulent hotels, Ms. Chen, 93, says she has a warning for the world.

Having lived through one of the most tumultuous periods in China’s recent history, Ms. Chen disputes the Communist Party’s sanitized version of its past and worries it has allowed it to continue making mistakes with global consequences.

Her voice drops, barely audible among the din of cutlery and diners in the restaurant: “When you do things in the spirit of Mao, that scares me,” she says, referring to China’s top leader, Xi Jinping.

Her books, she said, are meant to add “blood and flesh” to the official party account and help readers empathize with the Chinese people who have suffered under an authoritarian system. But her efforts have raised questions about whose voice matters when it comes to narrating Chinese history.

Ms. Chen is part of the increasingly small group of people still alive who endured the worst of Mao’s excesses. She says she wants to set the record straight. But her critics — mostly men — have raised doubts about the details of her recollections and accused her of being a fabulist.