The 1980s mark the first time the notion of a “sustainable diet” was introduced, gearing to dietary recommendations that would result in healthier environments and healthier consumers.
The successive state of thought on the global path of sustainable diets and biodiversity was first outlined in the book, “Sustainable Diets And Biodiversity—Directions And Solutions For Policy, Research, And Action,” presented at the International Scientific Symposium “Biodiversity And Sustainable Diets: United Against Hunger,” organized jointly by FAO and Bioversity International, held on November 3‒5, 2010 in Rome. The Symposium addressed for the first time the deep linkages among agriculture, biodiversity, nutrition, food production, food consumption, and the environment.
The Symposium served as a platform for reaching a consensus definition of “sustainable diets” and realizing the first set of UN development goals for the new millennium, the 2000‒2015 Millennium Development Goals.
With a dramatically increasing body of evidence of agriculture’s unsustainable nature as it is currently practiced in many parts of the world, renewed attention has been directed to sustainability in all its forms, including diets. The international community acknowledged that with a definition for “sustainable diets,” presented in a plenary session of the Symposium and accepted by the participants, as follows.
Sustainable diets with low environmental impacts contribute to food and nutrition security and 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.
Regardless of the many agricultural successes during nearly four decades, food systems—and diets—are still far from being sustainable as they should. Latest FAO data show that two billion people (a quarter of the global population) suffer from hunger; conversely, even more people (between a quarter and a third of the worldwide population) are overweight or obese. Curiously enough, both groups have something in common: a high prevalence of micronutrient malnutrition, a deficiency of essential nutrients, such as vitamins and minerals, for health maintenance.
The pivot of the discussion around sustainable eating is achieving better access to safe and high-quality food for more people populating the world while trying to minimize food waste and create an ecosystem that enables more resources to be redistributed in an ideal regenerative cycle.
It is then intuitive that improving nutrition through better balanced nutritious diets can address hunger issues and reduce the ecological impact of global dietary choices. A shift to more sustainable diets would encourage a higher diversification of what’s produced and consumed rather than a conversion to single-source nutritional patterns like the rampant veganism.
As a matter of fact, there are tradeoffs within all production systems to take into consideration when rethinking the interconnectedness of food systems. Consumers worldwide actually need to embrace a mix of different food sources for optimal wellbeing and equitable sustainability, especially when it comes to protein intake. It’s not about choosing traditional dairy protein over alternative plant-based protein; it’s about offering protein diversity.
When assessing the environmental impact of plant-based protein alternatives, the full value chain needs to be analyzed, including plant source diversification, regenerative agricultural practices, and food waste minimization. Without animals, many food side streams would be wasted, and marginal lands would no longer be productive.
Plant-based protein is a necessary component of sustainable nutrition for the collective future. Yet, no protein source is inherently ‘sustainable’ or ‘unsustainable.’ For plants, protein quality, extraction energy, yield per hectare, distribution, and further processing need to be considered. Over-reliance on a limited number of crops can cause the detrimental effect of water scarcity, deforestation, and biodiversity loss.
Besides being nutritionally superior to plant-based proteins in many aspects, such as providing all nine essential amino acids, dairy proteins offer significant functionality benefits. Cashing in on their quality difference, milk proteins can compensate for the lower essential amino acid composition of plant proteins, taking a ‘best of both worlds’ approach for consumers who want more plant-based products.
The flexitarian (or reducetarian) consumer is the main driving force behind the tremendous plant-based food market growth and the key to its coexistence with traditional dairy. This kind of savvy consumer seeks an optimal combination of health benefits, such as reducing the risk of chronic metabolic diseases and reinforcing the immune system, and environmental impact, like greenhouse gas (GHG) emissions.
Transformation to healthier and more sustainable diets for more people has a long road to go yet. In 2019, the EAT-Lancet Commission, consisting of 37 world-leading scientists of various scientific disciplines from 16 countries, was the first authority to analyze and propose the ideal path to healthier and more sustainable diets feeding up to 10 billion people by 2050 through a comprehensive and interdisciplinary report. The EAT-Lancet report is the first full scientific review of what constitutes a healthy diet from a sustainable food system and which actions can support and speed up food system transformation. Instead of presenting strict guidelines with little room for amendment, the report’s findings allow for independent decisions and local adaptation.
The approach of the EAT-Lancet Commission contemplating a perfect ‘planetary health diet’ includes:
- more than doubling the consumption of plant foods, such as fruits, vegetables, legumes, and nuts, and
- more than halving the consumption of added sugars and red meat.
A planetary health plate should consist by volume of approximately half a plate of vegetables and fruits. The other half, displayed by contribution to calories, should consist of primarily whole grains, plant protein sources, unsaturated plant oils, and (optionally) modest amounts of animal sources of protein.
Predicted change in food production from 2010 to 2050 (percent from 2010 scenario) for the business as usual (BAU) with full waste, the planetary health diet with full waste, and the planetary health diet with halved waste scenarios.
Although the planetary health diet provides a model to adopt for everyone, it doesn’t imply that the global population should adopt an exact dietary regime. Flexibility on local interpretation and adaptation of the universally-applicable planetary health diet is necessary and should reflect the culture, geography, and demography of the population and individuals.
Furthermore, some populations worldwide depending on agropastoral livelihoods still take advantage of traditional dairy products to obtain high-quality protein and essential micronutrients they wouldn’t otherwise be able to gather from limited accessibility to plant-based milk alternatives.