The healthiness and sustainability of national and global food based dietary guidelines: modelling study

Abstract

Objective: To analyse the health and environmental implications of adopting national food based dietary guidelines (FBDGs) at a national level and compared with global health and environmental targets.

Design: Modelling study.

Setting: 85 countries.

Participants: Population of 85 countries.

Main outcome measures: A graded coding method was developed and used to extract quantitative recommendations from 85 FBDGs. The health and environmental impacts of these guidelines were assessed by using a comparative risk assessment of deaths from chronic diseases and a set of country specific environmental footprints for greenhouse gas emissions, freshwater use, cropland use, and fertiliser application. For comparison, the impacts of adopting the global dietary recommendations of the World Health Organization and the EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems were also analysed. Each guideline's health and sustainability implications were assessed by modelling its adoption at both the national level and globally, and comparing the impacts to global health and environmental targets, including the Action Agenda on Non-Communicable Diseases, the Paris Climate Agreement, the Aichi biodiversity targets related to land use, and the sustainable development goals and planetary boundaries related to freshwater use and fertiliser application.

Results: Adoption of national FBDGs was associated with reductions in premature mortality of 15% on average (95% uncertainty interval 13% to 16%) and mixed changes in environmental resource demand, including a reduction in greenhouse gas emissions of 13% on average (regional range -34% to 35%). When universally adopted globally, most of the national guidelines (83, 98%) were not compatible with at least one of the global health and environmental targets. About a third of the FBDGs (29, 34%) were incompatible with the agenda on non-communicable diseases, and most (57 to 74, 67% to 87%) were incompatible with the Paris Climate Agreement and other environmental targets. In comparison, adoption of the WHO recommendations was associated with similar health and environmental changes, whereas adoption of the EAT-Lancet recommendations was associated with 34% greater reductions in premature mortality, more than three times greater reductions in greenhouse gas emissions, and general attainment of the global health and environmental targets. As an example, the FBDGs of the UK, US, and China were incompatible with the climate change, land use, freshwater, and nitrogen targets, and adopting guidelines in line with the EAT-Lancet recommendation could increase the number of avoided deaths from 78 000 (74 000 to 81 000) to 104 000 (96 000 to 112 000) in the UK, from 480 000 (445 000 to 516 000) to 585 000 (523 000 to 646 000) in the USA, and from 1 149 000 (1 095 000 to 1 204 000) to 1 802 000 (1 664 000 to 1 941 000) in China.

Conclusions: This analysis suggests that national guidelines could be both healthier and more sustainable. Providing clearer advice on limiting in most contexts the consumption of animal source foods, in particular beef and dairy, was found to have the greatest potential for increasing the environmental sustainability of dietary guidelines, whereas increasing the intake of whole grains, fruits and vegetables, nuts and seeds, and legumes, reducing the intake of red and processed meat, and highlighting the importance of attaining balanced energy intake and weight levels were associated with most of the additional health benefits. The health results were based on observational data and assuming a causal relation between dietary risk factors and health outcomes. The certainty of evidence for these relations is mostly graded as moderate in existing meta-analyses.

Fig 1

Overview of countries with food based dietary guidelines (FBDGs) and the average uncertainty score of each FBDG. Uncertainty was coded on a scale of 1 (low uncertainty) to 5 (high uncertainty) and averaged across recommendations for fruits and vegetables, legumes, nuts and seeds, whole grains, milk, eggs, fish, sugar, red meat, and processed meat. Appendix SI table 13 lists the uncertainty scores by food group

Fig 2

Percentage difference between recommendations from food based dietary guidelines (FBDGs) and current intake by food group and region. Positive values (in black) indicate greater intake in FBDGs and negative ones (in red) indicate lower intake. The comparison is based on recommended mean values. For the global FBDGs, the percentage changes between the guidelines and current intake is the average across all countries with a FBDG. WHO=World Health Organization; EAT=EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems

Fig 3

Number of food based dietary guidelines (FBDGs) recommendations that were achieved in each country. The number of recommendations included increases in fruits and vegetables, legumes, nuts and seeds, whole grains, and fish, as well as reductions in sugar and red meat and processed meat. The comparison is based on recommended mean values

Fig 4

Reduction in premature mortality (among ages 30-70) by region, scenario, and risk factor. The scenarios include adoption of national food based dietary guidelines (NDG), World Health Organization recommendations (WHO), and the EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems recommendations (EAT). Risk factors include reductions in intake of fruits, vegetables, legumes, nuts and seeds, whole grains, and fish, increases in intake of red and processed meats, and increases in the prevalence of underweight, overweight, and obesity. The health impacts associated with the combination of all risks is smaller than the sum of individual risks, because the former controls for coexposure (that is, each death is attributed to one risk factor only)

Fig 5

Change in environmental resource demand for adopting national or global (World Health Organization (WHO), EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems (EAT)) food based dietary guidelines (FBDGs) by food group and environmental domain. The environmental domains include food related greenhouse gas emissions (GHG), cropland demand (land), freshwater demand (water), nitrogen demand from fertilisers (nitro), and phosphorus demand from fertilisers (phos)

Fig 6

Comparison of the health and environmental impacts of universally adopting food based dietary guidelines (FBDGs) to a set of global health and environmental targets. Targets include the sustainable development goal of reducing premature mortality from non-communicable diseases (NCDs) by a third, the Paris Climate Agreement to limit global warming to below 2°C (greenhouse gas (GHG) emissions), the Aichi biodiversity target of limiting the rate of land use change (cropland), and the sustainable development goals and planetary boundaries related to freshwater use, and nitrogen and phosphorus pollution. Estimates are expressed as percentage of attained target value averaged across countries in FBDG regions. Values of 100% or less indicate that environmental and health impacts are in compliance with the targets, and values greater than 100% indicate that targets are exceeded. WHO=World Health Organization; EAT=EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems

Fig 7

Number of global health and environmental targets attained by country. Targets include the sustainable development goal of reducing premature mortality from non-communicable diseases by a third, Paris Agreement to limit global warming to below 2°C, Aichi biodiversity target of limiting the rate of land use change, and sustainable development goals and planetary boundaries related to freshwater use, and nitrogen and phosphorus pollution