It is a sad but well-known fact that current “standard” diets in most countries are neither healthy nor environmentally sustainable. Though many countries have healthy eating guidelines available for the public, and while the following of these is voluntary, they do offer some insight into how a country tries to offer guidance to their populations about what is healthy and what is not.

In this study, a group of researchers and scientists from the U.K., U.S., and Australia set off to quantify national food-based dietary guidelines (FBDGs) and assess their health and environmental impacts. Previously published associations with diet-related disease risks were used in the health analysis, where several food groups were classified as follows:

• recommended (fruits, vegetables, whole grains, legumes, nuts and seeds, and fish);
• neutral (milk, eggs, and poultry);
• discouraged (red meat, processed meat, and sugar). 

After exclusions, 86 national and two global (WHO and Lancet) guidelines were used throughout the analysis, where 11 risk factors and five disease endpoints were covered. To evaluate environmental effects, the authors used country and crop-specific environmental footprints for greenhouse gas emissions, cropland use, freshwater use, and fertilizer applications. 

In terms of guideline clarity, Europe scored the best, being evaluated at an uncertainty score of 2.9 (on a scale of 1 for low uncertainty to 5 for high uncertainty), followed closely by the Middle East and North America. Africa, on the other hand, exhibited the lowest clarity, with the most ambiguous instructions.

Current consumption patterns were found to fulfill some aspects of the national dietary guidelines, but no country simultaneously fulfilled all recommendations. In fact, of the 85 countries with national FBDGs, more than a quarter met no recommendations and nearly 90% met no more than two recommendations. The top-scoring nations, each fulfilling four recommendations, were Bangladesh, Indonesia, and Sierra Leone. Conversely, the United States did not attain any recommendations, whereas Canada only fulfilled those for the consumption of whole grains.

Successful adoption of national guidelines was associated with 15% reductions in premature, diet-related mortality. It is noteworthy that nearly half of the reductions were from improved weight levels. Across regions, the reductions varied from 6% in Africa, where communicable diseases are still behind a lot of the prevalent health problems, to 19% in North America. On the other hand, adopting a set of dietary recommendations developed by the EAT-Lancet Commission was associated with greater health benefits than the national guidelines or the ones proposed by the WHO.

Food-related greenhouse gas emissions were reduced on average by 13% across all countries, being positively impacted mostly by lower consumption of ruminant meat and offset by increases in milk consumption. On the other hand, the demand for cropland increased on average by 8%, due to higher consumption of milk, legumes, and fruits and vegetables.

In terms of mismatches between national guidelines and the food-related emission goals set out by the Paris Agreement, the targets were exceeded by 140% on average, ranging from 50% in Africa and 300% in North America. Only Indonesian and Sierra Leonean national guidelines were capable of fulfilling all six environmental targets. Overall, most were not compatible with global environmental targets and the sustainable development goals and planetary boundaries related to water use and fertilizer use. However, when comparing the different global guidelines, Lancet recommendations were associated with 39-69% greater reductions in greenhouse gas emissions due to more ambitious restrictions, with the greatest advantages posed by a vegan diet. 

A notable difference was that while most national guidelines recommended increasing dairy consumption, the EAT-Lancet recommendations suggest limiting dairy intake. Actually, the authors found that more than three-quarters of the increases in greenhouse gas emissions were from dairy. The basis for their decision to suggest strict limitations was an absence of clear associations between milk intake, bone health, and reduced risk of non-communicable diseases. Furthermore, they cite the existence of nutritionally adequate plant-based alternatives with more clearly associated reduced risks.  

Previous research indicates that nearly half of all national dietary guidelines still depict both plant and animal sources of protein together in the same “protein” category, while most countries offer no statement on the consumption of nuts and seeds. It is especially shocking than more than half of all countries have no national guidelines whatsoever. Out of those that do, however, vague recommendations are common. This causes problems, not only when analyzing potential implications, but also because the guidelines are at risk not being understood well by the general public. This is especially important in developing nations, where diets are projected to change towards the current Western model as income increases. The researchers suggest providing explicit targets for plant-based protein sources and recommendations to lower animal product consumption in order to bring national guidelines more in line with healthy and environmentally sustainable dietary patterns.

The analysis calls for reforms in FBDGs as they clearly could recommend healthier and more sustainable diets. Since global dietary guidelines typically argue for a reduction in the consumption of animal products, animal advocates will want to motivate national decision-makers to update current guidelines to the most progressive proposals issued by leading dietary organizations. The template offered by Lancet is seen as the most promising, with a reduction in animal product consumption, better human health outcomes, and reduced environmental impacts – the trifecta of modern dietary sustainability.