“There’s always been a war on fatness in [the U.S.],” says Edie Stark, a licensed clinical social worker and eating disorder expert. For a while, the body positivity movement pushed back on those ideals, encouraging people to embrace different shapes and sizes—even if diet culture never entirely disappeared. But now, the idea of thinness-as-status has been revived by GLP-1 drugs that put weight loss back into the spotlight.

But Adrienne Bitar, a lecturer on the history and culture of American food and health at Cornell University and the author of Diet and the Disease of Civilization, says it’s not just about body image. “Diets and fads—I think of them as sort of like clay. They are modeled according to the anxieties of the time,” she says. “The detoxification diet, for example, is a pretty direct reflection of concerns about environmental toxins and pollution. It came out of a long tradition that critiques the so-called toxic food environment.”

What’s shifted is how quickly—and how widely—these myths can spread. In the early 2000s, fashion magazines and diet books were primarily responsible for spreading misinformation. Now, it’s TikTok and Instagram.

“Anyone can say anything on social media or call themselves a coach; there’s no fact-checking,” says Stark. And most viewers lack the media literacy to distinguish between marketing and science. Parasocial relationships with influencers only blur the line further, making sales pitches feel like friendly advice.

Even as the language shifts—from “low-fat” to “clean eating,” from “dieting” to “wellness”—the values underneath haven’t budged. Thinness is still equated with discipline, morality, and beauty.