In an open letter to the editors of the journal, Katz and other researchers—including one of the authors of the new analyses, John Sievenpiper—objected to the guidelines as “highly irresponsible.” In a public statement, Sievenpiper said, “Unfortunately, the leadership of the paper chose to play up the low certainty of evidence by GRADE.” He suggested that even though evidence is not certain, it is not meaningless; a lack of definitive evidence that something is harmful is not itself reason to recommend that people do that thing. Other signatories of the letter included Harvard’s chair of nutrition, Frank Hu; the former surgeon general Richard Carmona; the former American College of Cardiology president Kim Williams; and the dean of Tufts University’s School of Nutrition, Dariush Mozaffarian.

Dean Ornish, a professor of medicine at the University of California at San Francisco who advocates for the medicinal value of plant-based diets, told me, “By their own analysis, the studies don’t show that there’s no benefit to cutting back on red and processed meat. So why would Annals publish this press release, and guidelines, saying otherwise?” Medical journals are not immune to the attention economy that influences all publishing, he posited, since they are judged by their “impact factor”—the number of times a journal is cited by others. (The journal’s editor, Christine Laine, said of this allegation that the new guidelines were “relevant to our readers” and displayed “methodologic rigor.”)