A green diet revolution? Calls for radical diet and food production intervention to improve health and the planet

17 Jan 2019 --- Feeding a growing population of 10 billion people by 2050 with a healthy and environmentally friendly diet will be impossible without dramatically transforming the global population’s eating habits, improving food production and reducing food waste. This is according to a Lancet commission of prominent academics that has put forward a planetary health diet.

“The food we eat and how we produce it determines the health of people and the planet and we are currently getting this seriously wrong,” says one of the commission authors Professor Tim Lang, University of London, UK.

Researchers are calling for a diet that consists of approximately 35 percent of calories as whole grains and tubers, protein sources mainly from plants – but including approximately 14g of red meat per day – and 500g per day of vegetables and fruits.

Moving to this new dietary pattern will require a drastic reduction of about 50 percent in the global consumption of foods such as red meat and sugar, while the consumption of nuts, fruits, vegetables and legumes must double.

These are dietary targets based on a 2,500 kcal/day diet. Image credit: The Lancet.Transformation of the global food system is urgently needed as more than 3 billion people are malnourished. Food production is also exceeding planetary boundaries by driving climate change, biodiversity loss and pollution due to the excessive use of nitrogen and phosphorus fertilizers, among others, the researchers warn.

Adding to the growing body of research into the ways in which environmental degradation and dietary patterns are linked, a newly published report by the EAT-Lancet Commission provides scientific targets for a healthy diet from a sustainable food production system. 

The report promotes diets consisting of a variety of plant-based foods, with low amounts of animal-based foods, refined grains, highly processed foods, added sugars and with unsaturated rather than saturated fats.

To improve both the environment and global eating patterns, dietary changes must be combined with improved food production and reduced food waste, the researchers say. 

The authors stress that unprecedented global collaboration and commitment will be needed, alongside immediate changes such as refocusing agriculture to produce varied nutrient-rich crops and increased governance of land and ocean use.

A “significant overhaul” is needed
“We need a significant overhaul, changing the global food system on a scale not seen before in ways appropriate to each country's circumstances,” says Lang. 

“While this is uncharted policy territory and these problems are not easily fixed, this goal is within reach and there are opportunities to adapt international, local and business policies. The scientific targets we have devised for a healthy, sustainable diet are an important foundation which will underpin and drive this change,” he adds. 

The commission is a three-year project that brings together 37 experts from 16 countries with expertise in health, nutrition, environmental sustainability, food systems, economics and political governance.

Despite increased food production contributing to improved life expectancy and reductions in hunger, infant and child mortality rates, and global poverty over the past 50 years, these benefits are now being offset by global shifts towards unhealthy diets.

The authors argue that the lack of scientific targets for a healthy diet have hindered efforts to transform the food system. 

Notably, the commission is foregoing a one-size-fits-all approach and putting forward that global targets will need to be applied locally. For example, countries in North America eat almost 6.5 times the recommended amount of red meat, while countries in South Asia eat only half the recommended amount. 

All countries are eating more starchy vegetables (potatoes and cassava) than recommended, with intakes ranging from between 1.5 times above the recommendation in South Asia and by 7.5 times in sub-Saharan Africa.

“The world’s diets must change dramatically. More than 800 million people have insufficient food, while many more consume an unhealthy diet that contributes to premature death and disease,” says co-lead Commissioner Dr. Walter Willett at Harvard University. 

“To be healthy, diets must have an appropriate calorie intake and consist of a variety of plant-based foods, low amounts of animal-based foods, unsaturated rather than saturated fats and few refined grains, highly processed foods and added sugars,” Willett says. 

“The food group intake ranges that we suggest allow flexibility to accommodate various food types, agricultural systems, cultural traditions and individual dietary preferences – including numerous omnivore, vegetarian and vegan diets,” he notes.

Impact on nutrition
The authors estimate that widespread adoption of such a diet would improve intakes of most nutrients. It would also increase essential micronutrient intake, such as iron, zinc, folate and vitamin A, as well as calcium in low-income countries. The exception is vitamin B12, where supplementation or fortification might be necessary in some circumstances.

They also modeled the potential effects of global adoption of the diet on deaths from diet-related diseases. Three models each showed major health benefits, suggesting that adopting the new diet globally could avert between 10.9 and 11.6 million premature deaths per year – potentially reducing adults deaths by between 19 and 23.6 percent.

The authors highlight that evidence about diet, human health and environmental sustainability is continually evolving and includes uncertainty, so they include ranges in their estimates, but are confident of the overall picture. 

“While major transformations to the food system occurred in China, Brazil, Vietnam, and Finland in the 20th century, and illustrate that diets can change rapidly, humanity has never aimed to change the food system this radically at such speed or scale,” says Professor Lang.

“People might warn of unintended consequences or argue that the case for action is premature, however, the evidence is sufficient and strong enough to warrant action, and any delay will increase the likelihood of not achieving crucial health and climate goals,” he adds.

Food sustainability
Unsustainable food production methods have been found to be the largest source of environmental degradation. To be sustainable, food production must occur within food-related planetary boundaries for climate change, biodiversity loss, land and water use, as well as for nitrogen and phosphorus cycles. However, production must also be sustainably intensified to meet the global population’s growing food demands.

This will require decarbonizing agricultural production by eliminating the use of fossil fuels and land use change losses of CO2 in agriculture. In addition, zero loss of biodiversity, net-zero expansion of agricultural land into natural ecosystems, and drastic improvements in fertiliser and water use efficiencies are needed.

The authors estimate the minimum, unavoidable emissions of greenhouse gases if we are to provide healthy food for 10 billion people by 2050. They conclude that non-CO2 greenhouse gas emissions of methane and nitrous oxide will remain between 4.7 and 5.4 gigatonnes in 2050, with current emissions already at an estimated 5.2 gigatonnes in 2010. 

This suggests that the decarbonisation of the world energy system must progress faster than anticipated, to accommodate the need to healthily feed humans without further damaging the planet.

Phosphorus use must also be reduced (from 17.9 to between 6 and 16 teragrams), as must biodiversity loss (from 100 to between 1 to 80 extinctions per million species each year).

“Designing and operationalizing sustainable food systems that can deliver healthy diets for a growing and wealthier world population presents a formidable challenge. Nothing less than a new global agricultural revolution,” says co-lead Commissioner Professor Johan Rockström, Stockholm Resilience Centre, Sweden and Potsdam Institute for Climate Impact Research, Germany.

“The good news is that it is not only doable, we have increasing evidence that it can be achieved through sustainable intensification that benefits both farmer, consumer and planet,” he adds.

“Humanity now poses a threat to the stability of the planet. Sustainability of the food system must therefore be defined from a planetary perspective. Five key environmental processes regulate the state of the planet. Our definition of sustainable food production requires that we use no additional land, safeguard existing biodiversity, reduce consumptive water use and manage water responsibly, substantially reduce nitrogen and phosphorus pollution, produce zero carbon dioxide emissions, and cause no further increase in methane and nitrous oxide emissions,” he says. 

Transforming the global food system
The commission proposes five strategies to adjust what people eat and how it is produced.

Firstly, policies to encourage people to choose healthy diets are needed, including improving availability and accessibility to healthy food through improved logistics and storage, increased food security and policies that promote buying from sustainable sources. Alongside advertising restrictions and education campaigns, affordability is also crucial, and food prices must reflect production and environmental costs. As this may increase costs to consumers, social protection for vulnerable groups may be required to avoid continued poor nutrition in low-income groups.

Strategies to refocus agriculture from producing high volumes of crops to producing varied nutrient-rich crops are needed. Currently, small and medium farms supply more than 50 percent of the essential nutrients in the global food supply. 

Global agriculture policies should incentivise producers to grow nutritious, plant-based foods, develop programs that support diverse production systems, and increase research funding for ways to increase nutrition and sustainability. 

In some contexts, animal farming is important to nutrition and the ecosystem and the benefits and risks of animal farming should be considered on a case-by-case basis.

Sustainably intensifying agriculture will also be key, and must take into account local conditions to help apply appropriate agricultural practices and generate sustainable, high-quality crops.

Equally, effective governance of land and ocean use will be important to preserve natural ecosystems and ensure continued food supplies. 

Lastly, food waste must be at least halved. The majority of food waste occurs in low- and middle-income countries during food production due to poor harvest planning, lack of access to markets preventing produce from being sold, and lack of infrastructure to store and process foods. Improved investment in technology and education for farmers is needed. 

Food waste is also an issue in high-income countries, where it is primarily caused by consumers and can be resolved through campaigns to improve shopping habits, help understand “best before” and “use by” dates, and improve food storage, preparation, portion sizes and use of leftovers, the research concludes.

Although the report sets out to tackle some pertinent global issues, some critics note that targeting agriculture may wrongly distract from a higher environmental priority – the burning of fossil fuels. 

Additionally, critics note that the report fails to make any persuasive case as to how its ambitious goals should be achieved, failing to mention the role of GM crops and importance of fertilizers and herbicides, among other issues.