Unacceptable use of substandard metrics in policy decisions which mandate large reductions in animal-source foods

Abstract

Many recent very influential reports, including those from the Global Burden of Disease (GBD) Risk Factor Collaborators, the EAT-Lancet Commission on Food, Planet, Health, and the Lancet Countdown on Health and Climate Change, have recommended dramatic reductions or total exclusion of animal-source foods, particularly ruminant products (red meat and dairy), from the human diet. They strongly suggest that these dietary shifts will not only benefit planetary health but also human health. However, as detailed in this perspective, there are grounds for considerable concern in regard to the quality and transparency of the input data, the validity of the assumptions, and the appropriateness of the statistical modelling, used in the calculation of the global health estimates, which underpin the claimed human health benefits. The lessor bioavailability of protein and key micronutrients from plant-source foods versus animal-source foods was not adequately recognised nor addressed in any of these reports. Furthermore, assessments of bias and certainty were either limited or absent. Despite many of these errors and limitations being publically acknowledged by the GBD and the EAT-Lancet authors, no corrections have been applied to the published papers. As a consequence, these reports continue to erroneously influence food policy decisions and international dietary guidelines, such as the World Wildlife Fund's Livewell Diet, and the Nordic Nutrition Recommendations 2023.

Fig. 1. Quantities of foods recommended by the EAT-Lancet Planetary Health Diet and the Adequate Diet for Adults.

Comparison of the percentages of calories provided by various food groups in the EAT-Lancet planetary health reference diet (panel a), and in a diet which provides sufficient micronutrients, the adequate diet for adults (panel b).

Fig. 2. Associations between unprocessed red meat consumption and cardiovascular outcomes.

Relative risk estimates from the GBD 2019 Risk Factors Study (panels a–c) and the Burden of Proof 2022 Study (panels d–f) for ischaemic heart disease, ischaemic stroke and haemorrhagic stroke, by levels of unprocessed red meat intake. Relative risks (95% confidence intervals) are plotted on the y-axis and unprocessed red meat intake (g/day) is plotted on the x-axis. The relative risk curves of the GBD 2019 Risk Factors Study (panels a–c) are for men and women aged 50–54 years, and were drawn using data from Table S7A of Supplementary Appendix 1. The relative risk curves of the Burden of Proof 2022 Study (panels d–f) are for adult men and women, and were drawn using data from Supplementary Table 7.

Fig. 3. Risk inflationary effects of default application of monotonic constraints.

Relative risk estimates from the Burden of Proof 2022 Study for breast and colorectal cancer, by levels of unprocessed red meat intake, both prior to (panels a and b), and after (panels c and d) application of a monotonic constraint. Relative risks (95% confidence intervals) are plotted on the y-axis and unprocessed red meat intake (g/day) is plotted on the x-axis. The relative risk curves are for adult men and women, and were drawn using data from Supplementary Fig. 1 (panels a and b) and from Supplementary Table 7 (panels c and d).