Guest essay by Eric Worrall
A study published in PNAS recommends climate be taken into consideration when drafting national recommended diet guidelines. The study further recommends that poor people should consume vegetable protein instead of meat protein, in line with dietary recommendations for rich countries.
The abstract of the study;
Evaluating the environmental impacts of dietary recommendations
Paul Behrensa, Jessica C. Kiefte-de Jong, Thijs Bosker, João F. D. Rodriguesa, Arjan de Koninga, and Arnold Tukkera
Dietary choices drive both health and environmental outcomes. Information on diets come from many sources, with nationally recommended diets (NRDs) by governmental or similar advisory bodies the most authoritative. Little or no attention is placed on the environmental impacts within NRDs. Here we quantify the impact of nation-specific NRDs, compared with an average diet in 37 nations, representing 64% of global population. We focus on greenhouse gases (GHGs), eutrophication, and land use because these have impacts reaching or exceeding planetary boundaries. We show that compared with average diets, NRDs in high-income nations are associated with reductions in GHG, eutrophication, and land use from 13.0 to 24.8%, 9.8 to 21.3%, and 5.7 to 17.6%, respectively. In upper-middle–income nations, NRDs are associated with slight decrease in impacts of 0.8–12.2%, 7.7–19.4%, and 7.2–18.6%. In poorer middle-income nations, impacts increase by 12.4–17.0%, 24.5–31.9%, and 8.8–14.8%. The reduced environmental impact in high-income countries is driven by reductions in calories (∼54% of effect) and a change in composition (∼46%). The increased environmental impacts of NRDs in low- and middle-income nations are associated with increased intake in animal products. Uniform adoption of NRDs across these nations would result in reductions of 0.19–0.53 Gt CO2 eq⋅a−1, 4.32–10.6 Gt PO3−4 eq⋅a−1, and 1.5–2.8 million km2, while providing the health cobenefits of adopting an NRD. As a small number of dietary guidelines are beginning to incorporate more general environmental concerns, we anticipate that this work will provide a standardized baseline for future work to optimize recommended diets further.
The study authors recommend that national recommended diet guidelines for poor countries be modified to reduce emphasis on increased meat consumption, instead emphasising increased consumption of nuts and fruits.
Results and Discussion
Characterization of Average and Recommended Diets. In general, NRDs are specific to the health challenges from diets found in that nation. For example, India focuses on increasing caloric and nutritional content (21), whereas the United States focuses on reducing caloric intake (22). Compared with average national diets, NRDs generally recommend a substantial reduction in sugars, oils, meat, and dairy (Fig. 1 and Figs. S2–S4). These reductions are largest in high-income nations, where fruit, vegetables, and nuts are generally recommended for replacement calories. These changes are very large and would require significant departures from current dietary patterns. It is likely that any shifts to these recommended diets would occur gradually. These general trends are similar for upper-middle–income nations but with less reduction in meat and several nations recommending replacement calories from dairy. India and Indonesia, both lower-middle–income nations, are the only nations with recommendations for increases in meat intake. This may be partly due to the relatively high prevalence of undernutrition and micronutrient deficiencies in these regions.
However, even in these cases the increase is small, and replacement calories from fruit, vegetables, and nuts are recommended, as in the case for high-income nations. In general, there is very little change in the consumption of fish in all nations, with high-income nations recommending a small reduction and middle-income nations recommending a moderate increase. Some eastern European nations have recommended diets showing very little change with respect to the average diet; this may be partially due to the fact that these guidelines have not been updated for some time and partly due to continuing concerns of undernutrition in some sectors (i.e., rural communities) of those societies (23, 24).
Further Opportunities in NRDs. The environmental impacts of NRDs vary widely among nations because their emphasis is driven by local dietary concerns (Fig. 2B and Fig. S2). Many middle-income nations have greater recommended meat intake than high-income nations, likely due to the relatively high prevalence of protein energy malnutrition and widespread micronutrient malnutrition, especially where large-scale food fortification programs have limited reach. These recommendations could be improved from an environmental perspective by advising the substitution of meat-based with plant-based proteins, such as legumes and nuts, as has been done in most high-income nations. Some nations recommend a reduction of red meat specifically or substitution with white meat for health reasons (31). Although this does align with environmental outcomes by reducing ruminant consumption, this still may lead to a relatively high (lean or white) meat intake, which has still disproportionate environmental impacts compared with other food types (32). Here we have focused on an isocaloric analysis whereby NRDs are altered such that the proportion of the different food categories matches that of the original NRD, but the overall caloric intake is scaled so that it matches that of the current average diet (Materials and Methods). An alternative way to harmonize the NRDs would be to scale the caloric intake not to a country-specific average but to the caloric intake recommended by global guidelines of ∼2,200 kcal⋅p−1⋅d−1 (33). National recommended diets average around that same value; thus, such an analysis would be very close to the analysis of the nonisocaloric NRD (Fig. S4).
The study authors don’t suggest how poor people could be discouraged from eating environmentally harmful meat proteins. No doubt the politicians who run poor countries will find a way, especially if access to UN environmental funding is contingent on achieving eco-friendly adjustments to national diets.