In a series of new reviews and guidelines published last week in the Annals of Internal Medicine, a panel of researchers argued that most adults need not cut back on red and processed meat for their health—a claim that runs counter to widely accepted recommendations from the American Heart Association, American Cancer Society, World Health Organization, and other organizations. Prominent nutrition experts have denounced the guidelines, with Walter Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, calling it “the most egregious abuse of data” he’d ever seen.
So how did the Annals authors arrive at such a controversial stance? Referencing data from more than 100 nutrition studies, the researchers acknowledged a link between consumption of red and processed meat and increased risk of developing chronic diseases. But they went on to conclude that because the evidence was taken largely from observational research and potentially “unreliable” self-reports of food consumption, it should not be the basis of recommendations to eat less meat.
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“The statisticians’ findings are entirely consistent with what we already knew to be true, but they are issuing guidelines that recommend the opposite anyway, on the basis of their own contrived technicality: they deem their own findings highly uncertain,” writes David Katz, MD, founding director of the Yale Prevention Research Center. Additionally, Katz notes that the analyses do in fact omit several reputable trials and other key data on the dangers of eating red and processed meat.
The guidelines’ authors contended that a more reliable research method would be to only use randomized controlled trials, with experimental and control groups that show cause and effect. But, as Katz explained in a recent interview with Forks Over Knives, that’s unrealistic when studying health hazards: “Scientists who have devoted whole careers to studies of nutrition know we cannot rely solely on randomized trials. Who is willing to be randomly assigned to some diet for the rest of their life?”
Katz imagines if the Annals authors applied the same logic to smoking: “Since there are few if any randomized trials of smoking, they conclude that they have very low confidence in the reliability of their own [observational] findings. On that basis, they publish guidelines recommending that the public simply continue to smoke.”
The Physicians Committee for Responsible Medicine has filed a federal petition against Annals to correct the record. “Abundant evidence links red and processed meat consumption to heart disease, cancer, and increased risk of premature death,” notes PCRM President Neal Barnard, MD. “Even eating just one slice of bacon a day is linked to higher risk of colorectal cancer. The majority of American adults are overweight, 30 percent have prediabetes or diabetes, and cardiovascular disease and cancer take an enormous toll, due, in part, to dietary choices that are influenced by advertisements such as this.”
The bottom line: Eating less red and processed meat and moving to a whole-food, plant-based diet is still the best thing you can do to improve your health, prevent chronic diseases, and lower your carbon footprint.