In 2019, Annals of Internal Medicine published a series of reviews and a set of guidelines that argued there was insufficient evidence to link meat consumption to heart disease, cancer, or overall mortality and, consequently, insufficient evidence to support prior recommendations to reduce meat intake (1). This recent JAMA piece reviews the responses from supporters and detractors of the controversial series and guidelines, providing insight into a dramatic behind-the-scenes scramble to preserve the dominance of the anti-meat scientific consensus.
The Annals papers, published in November 2019, evaluated research from observational studies and controlled trials investigating the relationship between meat intake and disease. They applied the GRADE methodology to this data, which places greater weight on evidence derived from controlled trials than observational data. The group found a small but uncertain association between increased meat intake and ill health in the epidemiological data, but no link between meat and cancer, heart disease, or death from any cause from 12 randomized controlled trials enrolling 54,000 total participants. They consequently concluded there was insufficient evidence to discourage meat consumption. An accompanying letter summarized these points.
Just before publication, Christine Laine, editor-in-chief of the journal, received around 2,000 emails, many of which were clearly the result of an automated script. She noted the tone of the emails was “particularly caustic” and even more vitriolic than the response the journal had previously received from the NRA after publishing research on firearm injury prevention.
This email response was coordinated by True Health Initiative (THI), a nonprofit led by David Katz, whose team includes Dr. Walter Willett, a faculty member in the Harvard School of Public Health who has been described as “the world’s most influential nutritionist.” THI members received the articles five days prior to their publication; by the next day, Katz and 11 other THI members sent a letter to Laine asking for the preemptive retraction of the paper. Signatories included Willett, his Harvard colleague Frank Hu, and former Surgeon General Richard Carmona. According to Annals media relations manager Angela Collom, this response represented a violation of the journal’s embargo policy; Katz was subsequently dropped from the list of individuals receiving advanced access to articles.
Katz later described the articles as “a great debacle to public health” and likened the recommendations to terrorism. Another signatory, Neil Barnard, filed for the City of Philadelphia and the FTC (in two separate petitions) to block the publication of the reviews, citing them as a public danger. Later, at a cardiology conference, Willett presented a slide representing the journal, Dr. Gordon Guyatt (who chaired the panel that created the guidelines and was a contributing author to the reviews), and New York Times reporter Gina Kolata (who first reported on the papers) as sources of “disinformation.”
Soon after the guidelines were published, the Harvard School of Public Health posted a response, arguing the use of the GRADE methodology was “problematic” and the guidelines should not change previous recommendations against meat consumption.
Katz has criticized the use of GRADE in nutrition research, arguing the use of randomized controlled trials to study nutrition is infeasible. He and Willett have proposed an alternative review methodology, HEALM, which allows scientific conclusions to be more easily drawn directly from epidemiological research. Katz describes himself as “not anti meat … just pro-science,” despite his promotion of what many would argue is a weaker or even un-scientific experiment design for nutrition research.
Guyatt described the negative response to the Annals series and guidelines as both “predictable” and “hysterical.”
The New York Times and others reported that Bradley Johnston, lead author of the guidelines, had failed to disclose receiving funding from the International Life Sciences Institute (ILSI), an organization CrossFit has been strongly critical of in the past and which receives heavy industry funding. Johnston argued this disclosure was not required, as the funding was outside the three-year disclosure reporting period required by Annals; in The New York Times piece, he described his decision to take ILSI funding as “naive.” Other members of the group had additional conflicts, including John Sievenpiper (ILSI) and Patrick Stover, who, like Johnston, had received funding from Texas A&M AgriLife, which receives a small amount of funding — about 1.5% of total income — from the cattle industry.
Katz’s organization has received support from organizations advocating for plant-based diets, the olive industry, the nut industry, and multiple food industry companies. Katz himself has received industry funding from a wide variety of sources. The Chan School of Public Health at Harvard, Willett and Hu’s home institution, has also received funding from the walnut industry (2). Carmona serves on the board of Herbalife. With convenient equanimity, Katz has described these industry ties as a “confluence of interest” rather than a conflict.
The Annals series and other relevant references are briefly summarized below.