The food we eat affects our health, and that of our planet. Food insecurity, poor nutrition and climate change are some of the global major challenges. Malnutrition for instance, which includes micronutrient deficiencies and obesity, has a devastating impact on health. According to published by the Food and Agriculture Organization (FAO) of the United Nations, over 800 million people went hungry in 2020.
More concerning is that these figures are likely to be higher as they do not consider the effects of the still ongoing COVID-19 pandemic. It is estimated 462 million people are underweight while a staggering 2 billion adults are overweight or obese. Moreover, as per the report of the Intergovernmental Panel on Climate Change, it is estimated that the food system is responsible for about 20-30% of global greenhouse gas emissions.
Considering this, the food system needs to be transformed to improve health, increase food production and nutrition security, and limit the damage to the planet. A solution might be to move towards healthier and environmentally sustainable diets, both affordable and accessible. Professor Jennie Macdiarmid and colleagues from the , a member institution of the United Nations Academic Impact (UNAI) in the United Kingdom, have been researching this issue.
They have been exploring what sustainable diets could comprise, but also, fundamentally how consumers may be encouraged to change their current dietary habits. Of course, dietary changes needed will vary across different economies, with higher income countries, for instance, encouraged to make dietary changes to reduce consumption of foods contributing to high emissions, such as animal-based foods as these are associated with high greenhouse gas emissions.
In 2010, a joint report entitled , defined sustainable diets as those “with low environmental impacts which contribute to food and nutrition security and to healthy life for present and future generations. Sustainable diets are protective and respectful of biodiversity and ecosystems, culturally acceptable, accessible, economically fair and affordable; nutritionally adequate, safe and healthy; while optimizing natural and human resources.”
This provides the benchmark for future diets but translating this comprehensive definition into practice and how best to bring together all these attributes might be challenging. The first study made by the researchers at the University of Aberdeen explored what sustainable diets could look like in practice. They used mathematical modeling techniques to create diets that met nutrient requirements, while at the same time would reduce greenhouse gas emissions.
Importantly, this was based on typical diets in the United Kingdom as the starting point for change for it to be familiar to consumers. The greatest reduction in greenhouse gas emissions is achieved by eliminating meat and dairy from the diet, but since less than 1% of the population in that country consumes a vegan diet, these changes are unlikely to be acceptable to the vast majority of the population.
Furthermore, removing all animal products needs to be carefully managed to prevent micronutrient deficiencies, because animal-based foods are rich sources of these nutrients. Nutrients from plant-based foods are also less bioavailable in digestion. Building on this research, focus groups and behavioral experiments with adults and young people set out to explore attitudes toward sustainable diets and the willingness to make changes, especially eating less meat.
The results showed a reluctance to reduce meat consumption. Despite being concerned about climate change, few were aware of the link with food. They saw other behaviors, such as recycling or reducing packaging, as more acceptable. Going forward, other environmental attributes were added to the models to determine the contribution of the current diet in the United Kingdom to land use both domestically and abroad and how this land footprint could be reduced.
Like greenhouse gas emissions, livestock and production of feed required the most land, but other commodities such as coffee and cocoa accounted for much of the land use abroad for the diet in the United Kingdom. Alongside other studies, this research clearly illustrates among other things, the complexity of sustainable diets in practice and being able to ensure that they are affordable and accessible.
It is not an easy task, and a holistic approach is needed to address ways to shift the population to more sustainable diets. This allows the reduction of trade-offs between key attributes such as nutrition, environment, habitual consumption patterns, affordability, and the desirability and acceptability of a diet. Evidence from these studies was used to develop the Guiding Principles for Sustainable Healthy Diets published by the FAO and the World Health Organization.
Research from the University of Aberdeen has improved the understanding of sustainable diets at a critical time when solutions are needed to tackle climate change and the global health crisis. It is also connected with the overall , particularly .
