With 690 million people going hungry, obesity levels rising almost everywhere and agriculture contributing a third of greenhouse gas emissions, it is clear that global diets need to change.
And we have more information than ever before about what that involves. Yet dietary advice until now has been insufficient to influence food habits and consumer behaviour for the better fast enough to find the perfect balance.
To allow everyone, everywhere to take up a healthy and sustainable diet better placed to contend with the challenges of the Anthropocene, we need an approach that overcomes at least three barriers to better nutrition in the interests of both people and the planet.
The first is a lack of diversity and inclusivity. Many popular diets are based on the principle of exclusion, whether some or all meat, dairy, or carbohydrates, which also means excluding any nutritional value of these broad food groups.
Placing wholesale restrictions or limits on food consumption also makes a diet more challenging to follow and as a result, more likely to fail. Moreover, by encouraging consumers to give up certain foods, such diets are also concentrating demand on fewer products, which has an impact on farmers’ livelihoods and crop diversity.
A better approach would be to focus instead not on the food type but on the frequency with which it is eaten.
More people are likely to be able to maintain a diet that requires them only to reduce how often they eat foods associated with a higher risk of heart disease and climate impact, and collectively, these changes will bring down both illness and emissions. Healthy and sustainable diets can reduce food-related greenhouse gas emissions by at least 30 per cent and wildlife loss by up to 46 per cent.
Secondly, existing guidelines tend to overlook cultural and social factors that influence dietary choices.
Attempts to develop a universal diet, such as an entirely plant-based diet, ignore the cultural role played by livestock and animal-source foods in many parts of the world, particularly in arid areas where growing crops is challenging if not impossible. Moreover, this approach may lead to an inadequate intake of some of the nutrients necessary for health.
Conversely, one of the successes of the Mediterranean diet, which is widely accepted to promote good health and agroecological practices, is its strong ties to social and cultural heritage.
Social interaction is an influential factor for making decisions about food, with studies showing that people who eat alone are less likely to prepare boiled vegetables and salads than when they cook for others, for example.
Affordability must also be factored into dietary advice. Globally, the cost of a healthy diet surpasses the international poverty line of $1.90 a day, resulting in unaffordable choices for more than three billion people as of 2017.
The final barrier to enabling consumers to take up and maintain a healthy, sustainable diet is the ability to adapt to local conditions and environments. Consumers will be unable to commit to eating in a certain way if they are unable to consistently grow or access the kinds of produce that they recognise and enjoy.
By remodelling the traditional food pyramid as the “Double Health and Climate Pyramid” for seven different regions, research by the Barilla Foundation shows that healthy, sustainable diets are possible almost anywhere because every culture has the food groups needed to have a delicious and varied diet. At the same time, this approach allows everybody to increase the variety and the appeal of their diets by choosing healthy and sustainable foods, not only from their own culinary context but also from other gastronomical cultures where appropriate.
This science-based approach aligns food groups with the greatest health benefits with those that have the lowest environmental impact to create a simple framework to guide diets without excluding anything.
So while a healthy and sustainable diet includes a large share of plant-based foods, it also allows for a variety of protein sources, mainly legumes and nuts, but also dairy, fish, poultry and eggs.
Diets with a higher intake of plant foods are associated with a substantially better health profile compared with diets including predominantly animal foods, but a healthy, sustainable diet can also comprise fish, dairy and poultry, which have medium to low carbon footprints.
There are multiple types of a sustainable diet, and these can be pursued in different contexts, in a way that is accessible, affordable, safe, equitable and culturally acceptable.
So many of the challenges the world faces right now are man-made, which means that mankind has the power to solve them. We know that our global diets need to change, but the most effective change will be one that people can adopt and maintain in the long-term.
The Double Pyramid offers a new tool to lay the foundation for a new dietary movement that means we can still take pleasure in the foods we love, while meetings the needs of our bodies and our climate