The new guidelines were released in Annals of Internal Medicine, a prestigious medical journal published by the American College of Physicians. Robert McLean, the ACP’s president and a rheumatologist at Yale, told me that they were the result of an editorial decision by the journal, not the ACP, but he nevertheless defended the analyses. “They did not say that eating red meat is safe,” he said. “They said that the data suggesting it’s as harmful as we once thought is inconclusive. They’re not saying to go out and eat all the red meat you want.”

The news alerts came down to the sixth article, which was the set of “clinical guidelines.” In it, the researchers concluded that because of the “low quality evidence,” adults should continue eating meat as they do. To arrive at this conclusion, the authors used a technique known as GRADE, which subjectively evaluates different types of evidence. For example, a drug would not simply be recommended because it is effective; the amount of effect would be considered alongside things such as reliability, side effects, and other costs. Based on its analysis, the group decided that the evidence of meat’s harms to health was not strong enough to recommend that people stop eating meat altogether. And because it deemed this evidence weak, it chose to recommend that people do not attempt to change their habits.

Typically, a medical journal publishes its findings and then gives some analysis of what those findings might mean, but it is unusual for authors to extrapolate findings into recommendations. It is especially rare when the directives bear on heart disease, the No. 1 killer of humans. And incorporating patient preferences into the guidelines themselves is controversial. History would likely be different if findings in the 1960s that cigarettes cause lung cancer had been translated into clinical guidelines where harms were negated by people’s enjoyment of cigarettes.

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.