The global food system is a major driver — if not the major driver — of climate change, water stress, land use, biodiversity loss, soil erosion, deforestation and the depletion of fish stocks. (1, 2, 3)
A growing global population — which is estimated to reach over nine billion by 2050 and which is rising in tandem with a trend toward a more ‘Western’ style of eating — will require more food to be produced in the coming decades, particularly meat and animal products. (4)
If we carry on as we are, experts suggest we will need to double food production by 2050 compared to 2010. (5) This will require 120% more water and 42% more cropland, which will result in the loss of 14% more forest and much of the world's biodiversity as well as the release of enough carbon dioxide to create 2 degrees of global warming (6). Scientists warn that if this 2oC limit is exceeded, we'll see widespread extinction of animal and plant species, more frequent droughts, a rise in sea level and an increased risk of flooding in certain areas.
How do we meet the world's growing food demands, particularly for animal foods, and prevent further damage to the planet? One answer is to eat a plant-based diet. Research has shown plant foods to be more environmentally friendly than animal foods, as they require less land, water, and energy to produce and generate fewer GHGe. (1, 7, 8, 9, 10). Studies examining differing dietary patterns have also found that diets featuring more plant foods and fewer animal products have a lower environmental impact. The greater the restriction of animal foods, the smaller the environmental footprint. (11)
A review of 60 studies found that by switching to a more sustainable diet, GHGe and land use could be reduced by as much as 70-80% and water use could be reduced by as much as 50%. Examples of these sustainable diets include vegetarian, vegan, and pescatarian diets; replacing ruminant (beef, lamb) with monogastric (chicken, pork) meat; balanced energy intake; following healthy guidelines; the Mediterranean diet and the New Nordic diet; and so on. The largest environmental benefits were seen in those diets that most reduced the amount of animal-based foods featured. (3)
Sustainability comprises three dimensions — the social, the environmental and the economic.
The Food and Agricultural Organisation (FAO) of the United Nations have incorporated these dimensions into their definition of sustainable diets:
‘Sustainable diets have low environmental impacts and 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…’(5)
To date, most of the research defining sustainable diets has focused on nutrition, health and the environment. As a result, we now have a pretty good idea of what a more environmentally friendly, health-supportive diet looks like.
As an example, one report reviewed the scientific literature examining the role of reducing animal foods consumption in meeting climate change targets (12). It found that substantial global reductions in meat intake by 2050 could reduce agriculture‐related emissions by 55% to 72%, with even greater reductions from also reducing dairy and eggs. Additionally, global reduction in meat and dairy intake of 75% by 2050 could reduce emissions by an amount greater than the emissions from the entire transportation sector in 2010.
Numerous organisations have identified the main characteristics associated with a sustainable diet based on nutritional, environmental and health elements (13, 14, 15, 16, 17, 18, 19). The common theme across all of these recommendations is to eat less meat and dairy foods, and eat more plant foods.
In the UK, the Carbon Trust has calculated if we were to eat according to the dietary recommendations outlined in the new Eatwell Guide, we would reduce GHGe, water use and land use to the point that each of these would be brought within globally sustainable levels (20). This would require ‘fruit and vegetable’ consumption to increase by 54%; ‘starchy foods’ consumption to increase by 69%; ‘beans, pulses, fish, eggs and meat’ consumption to fall by 24%; and ‘dairy group’ consumption to fall by 21%, compared to current intakes (21).
The area of sustainable diets is important and fast-moving, and within just the past few months, the EAT–Lancet Commission was published. This report brought together 37 industry-leading scientists to reach a scientific consensus that defines a healthy and sustainable diet (22).
Step 1: Reduce food waste. Currently, around one-third of all purchased food is thrown away.
Step 2: Eat a balanced, varied diet to meet calorie requirements. Globally we eat around 20% more than we need to.
Step 3: Eat fewer foods that are high in fat, sugar and salt
Step 4: Eat more fruits and vegetables — at least five per day. Choose seasonal, field grown, and less fragile varieties to avoid spoilage.
Step 5: Base meals on starchy foods like bread, potatoes, pasta and other grains, and choose whole grains whenever possible.
Step 6: Moderate meat intake, limit processed meats, and enjoy more plant-based protein sources like peas, beans, nuts and lentils
Step 7: Advise a change from dairy products to oat drinks. According to a life cycle analysis (LCA) based on Swedish conditions, the production of oat drinks results in 80% less GHGe and requires 79% less land use and 60% less energy use than cow's milk production (23). See figure 1 below.
Step 8: Choose unsaturated fats and oils, e.g. rapeseed oil, and consume it in small amounts.
1. Vermeulen SJ, Campbell BM, Ingram JIS. (2012) Climate change and food systems. Annu Rev Environ Resour; 37:195–222.
2. Garnett T. (2014) What is a Sustainable Healthy Diet? A Discussion Paper. Oxford: Food Climate Research Network.
3. Steinfeld H, et al. (2006) Livestock Long Shadow: Environmental Issues and Options. Rome: FAO
4. United Nations Department of Economic and Social Affairs Population Division (2015) World Population Prospects: The 2015 Revision, Key Findings and Advance Tables. Working Paper No. ESA/P/WP.241
5. Food and Agriculture Organization (2010) International Scientific Symposium. Biodiversity and Sustainable Diets – United against Hunger
6. Bajzelj B, et al. (2014). Importance of Food-Demand Management for Climate Mitigation. Nature Climate Change; 4: 924-29
7. Ranganathan, J. et al. (2016). Shifting Diets for a Sustainable Food Future. Working Paper, Instalment 11 of Creating a Sustainable Food Future. Washington, DC: World Resources Institute.
8. Audsley et al. (2009) How low can we go? an assessment of greenhouse gas emissions from the UK food system and the scope to reduce them by 2050. Food Climate Research Network & WWF, London, UK
9. Carlsson-Kanyama A, Gonzalez A (2009) Potential contributions of food consumption patterns to climate change. Am J Clin Nutr; 89: 1S–6S
10. Committee on Climate Change (2010) The fourth carbon budget. Reducing emissions through the 2020s. Committee on Climate Change, London, UK
11. Aleksandrowicz L, et al. (2016) The Impacts of Dietary Change on Greenhouse Gas Emissions, Land Use, Water Use, and Health: A Systematic Review. PLoS ONE; 11(11): e0165797
12. Brent K, et al. (2015) The Importance of Reducing Animal Product Consumption and Wasted Food in Mitigating Catastrophic Climate Change.
13. DEFRA, (2013) Sustainable Food Consumption Follow-up to the Green Food Project.
14. Dibb S, Fitzpatrick I (2014) Let’s talk about meat: changing dietary behaviour for the 21st century. Eating Better.
15. Sustainable Development Commission (2009) Setting The Table; Advice to Government on priority elements of sustainable diets.
16. WWF, (2011) Livewell: a balance of healthy and sustainable food choices.
17. WWF, (2013) Livewell for Live. Adopting healthy sustainable diets.
18. Harmon, A.H. and B.L. Gerald, (2007) Position of the American Dietetic Association: food and nutrition professionals can implement practices to conserve natural resources and support ecological sustainability. J Am Diet Assoc; 107(6): 1033-43
19. Garnett T (2014) Changing What We Eat: A Call for Research and Action on Widespread Adoption of Sustainable Healthy Eating. Food Climate Research Network.
20. Carbon Trust (2016) The Eatwell Guide: a more sustainable diet report
21. Scarborough P, et al. (2016) Eatwell Guide: modelling the dietary and cost implications of incorporating new sugar and fibre guidelines BMJ Open; 6:e013182. doi: 10.1136/bmjopen-2016-013182
22. Willett, W W, et al. (2019). Food in the Anthropocene: the EAT–Lancet Commission on healthy diets from sustainable food systems. The Lancet Commissions; 393(10170):447-492 https://eatforum.org/eat-lancet-commission/. Accessed February 2019.
23.Florén et al (2013) Lifecycle analysis conducted on behalf of Oatly (Swedish Conditions). SIK, SP group (SP Technical Research Institute of Sweden). Unpublished but available on request.