If humanity does not change its ways, we face impending environmental breakdown and climate collapse. Changing what we eat is one major step to preventing this.
Introduction
It might come as a surprise, but agriculture has a really big impact on the environment. If we quantify the impact of the food system across the lifecycle, from production to consumption (Figure 1), the food system is responsible for ~34% of global greenhouse-gas emissions (GHGe) (1), it takes up ~40% of habitable (ice-free) land surface (2), and accounts for ~70% of global freshwater use (3). What’s more, the overuse of nitrogen and phosphorus fertilisers damages ecosystems and pollutes waterways (3).
Figure 1. The stages involved in the food system (4). Each stage impacts the environment.
While it is inevitable that the food system will impact the environment to some extent, you will be glad to know that it doesn’t have to be quite as environmentally damaging as it currently is. This is because different foods have drastically different environmental impacts. Therefore, it is crucial that we move towards producing (and eating) more sustainable foods. In fact, shifting to a more sustainable food system is necessary if we are to meet global climate targets (5).
What is a Sustainable Diet?
Sustainable diets are largely plant-based in nature because plant-source foods (e.g., fruits, vegetables, legumes) generally have a lower environmental impact than animal-source foods (e.g., beef, pork) (Figure 2). Of all animal-source foods, red meat and dairy are the most environmentally intensive. In fact, red meat and dairy production accounted for ~57% of agricultural GHGe in 2020 (6), which is due to direct methane emissions from cow burps (methane is a particularly potent greenhouse gas), as well as carbon emissions from the deforestation necessary to grow livestock feed and to provide pastureland (7).
Figure 2. Environmental impacts of various food categories (3). As you can see, healthy plant-source foods have a lower impact than animal-source foods across the board.
The Planetary Health Diet—which was created by 37 world-leading scientists from across the globe as part of the EAT-Lancet Commission (3)—provides an example of a diet that would keep our food system within a safe operating space for the planet, while also being healthy (Figure 3). Therefore, it gives us an insight into the direction our diets must shift towards if we are to reduce the food system’s outsized impact on the environment. However, it is not meant to be an exact dietary prescription, and it may need to be adapted to your individual needs to ensure you get all of your nutrients (8). For example, this diet may not provide enough iron for menstruating females, so eating more meat/fish or iron-fortified foods (e.g., Weetabix) may be necessary (8).
Taking a multivitamin is also an option to help ensure you’re getting enough nutrients when eating a sustainable diet, and for athletes, supplementing with iron may be necessary for some because iron requirements are even higher if you regularly exercise. In addition, athletes will need a higher protein intake than most, but sourcing this extra protein from plant protein sources would be more environmentally sustainable than from animal protein sources. And once you’re eating enough total protein (i.e., ~1.6 grams per kilogram of body weight), plant protein will support your gains just as well (check out our previous article on that topic if you’re interested!).
Figure 3. The food group components of the Planetary Health Diet (7). The recommended daily intakes (given in grams) are based on a total energy intake of 2,500 calories per day.
Eating to Save the Planet
Now that you know what an environmentally sustainable diet looks like, you can make changes to reduce your diet-related environmental impact. Here are my top three tips to make your diet more sustainable (and healthy!):
Incorporate more legumes (e.g., beans, lentils, soy foods) into your diet in place of meat (especially red meat). A study from the US estimated that if everyone swapped their beef intake for beans, 42% of cropland could be spared and GHGe would be massively reduced (9). Likewise, in Sweden, a 50% reduction in meat intake in favour of home-grown legume consumption was modelled to reduce GHGe and land use by 20% and 23%, respectively, while ensuring the diet was still nutritionally adequate (10).
Increase your fruit and vegetable intake. As you can see in Figure 2, fruits and vegetables have a low environmental impact, and greater intakes of these foods are also associated with a reduced risk of heart disease, cancer, and death from any cause (11).
Increase your intake of nuts and seeds. Nuts and seeds are likewise low-GHGe foods (Figure 2) and are full of heart-healthy mono- and polyunsaturated fats, which are associated with a reduced risk of heart disease—likely due to their ability to lower low-density lipoprotein (LDL) cholesterol (12).
Check out this delicious bean chilli recipe!
Summary
While the prospect of environmental breakdown is on the horizon, it is not inevitable, and if we all ate a more sustainable diet, we would be in a much better position than we are today. What’s more, eating this way is also a good move for your health, making sustainable (and healthy) diets a win-win for the planet and us.
Training121 will be sponsoring and attending the UCD PLAN’EAT Living Lab Spring Festival on April 10th in the UCD Village, so do come along to that if you’re a UCD student and sign up to hear from award-winning author of An Irish Atlantic Rainforest, Eoghan Daltun, discuss his fascinating story on the day. And if you are a first or second year undergraduate UCD student, you can join the UCD PLAN’EAT Living Lab through this link to learn more about sustainable diets and experience a range of benefits! For full disclosure, outside of my work with Training121 I am a PhD student with the UCD PLAN’EAT team.
As always, thanks for reading. I wish you all a lovely weekend!
Patrick Elliott, BSc, MPH
Health and Nutrition Science Communication Officer at Training121
Instagram: @just.health.info
Twitter/X: @PatrickElliott0
References
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(2) Smith P, Bustamante M, Ahammad H, Clark H, Dong H, Elsiddig EA, Haberl H, Harper R, House J, Jafari M, Masera O, Mbow C, Ravindranath NH, Rice CW, Robledo Abad C, Romanovskaya A, Sperling F, and Tubiello F, 2014: Agriculture, Forestry and Other Land Use (AFOLU). In: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Edenhofer O, Pichs-Madruga R, Sokona Y, Farahani E, Kadner S, Seyboth K, Adler A, Baum I, Brunner S, Eickemeier P, Kriemann B, Savolainen J, Schlömer S, von Stechow C, Zwickel T, Minx JC (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Available at: https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_chapter11.pdf
(3) Willett W, Rockström J, Loken B, Springmann M, Lang T, Vermeulen S, et al. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet. 2019;393(10170):447–92. Available at: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31788-4/fulltext
(4) Cucurachi S, Scherer L, Guinée J, Tukker A. Life Cycle Assessment of Foods. One Earth. 2019;1(3):292–97. Available at: https://www.sciencedirect.com/science/article/pii/S2590332219301289
(5) Harwatt H, Ripple WJ, Chaudhary A, Betts MG, Hayek MN. Scientists call for renewed Paris pledges to transform agriculture. Lancet Planet Health. 2020;4(1)e9–10. Available at: https://www.sciencedirect.com/science/article/pii/S2542519619302451
(6) Romanello M, Napoli Cd, Green C, Kennard H, Lampard P, Scamman D, et al. The 2023 report of the Lancet Countdown on health and climate change: the imperative for a health-centred response in a world facing irreversible harms. Lancet. 2023;402(10419):2346–94. Available at: https://www.sciencedirect.com/science/article/pii/S0140673623018597
(7) Elliott PS, Devine LD, Gibney ER, O’Sullivan AM. What factors influence sustainable and healthy diet consumption? A review and synthesis of literature within the university setting and beyond. Nutr Res. 2024. Available at: https://www.sciencedirect.com/science/article/pii/S0271531724000368
(8) Beal T, Ortenzi F, Fanzo J. Estimated micronutrient shortfalls of the EAT-Lancet planetary health diet. Lancet Planet Health. 2023 Mar;7(3):e233–7. Available at: https://www.thelancet.com/journals/lanplh/article/PIIS2542-51962300006-2/fulltext
(9) Harwatt H, Sabaté J, Eshel G, Soret S, Ripple W. Substituting beans for beef as a contribution toward US climate change targets. Clim Change. 2017;143(1):261–70. Available at: https://link.springer.com/article/10.1007/s10584-017-1969-1
(10) Röös E, Carlsson G, Ferawati F, Hefni M, Stephan A, Tidåker P, et al. Less meat, more legumes: prospects and challenges in the transition toward sustainable diets in Sweden. Renew Agric Food Syst. 2020;35(2):192–205. Available at: https://www.cambridge.org/core/journals/renewable-agriculture-and-food-systems/article/less-meat-more-legumes-prospects-and-challenges-in-the-transition-toward-sustainable-diets-in-sweden/4B3B9B479B1B407B148D60860F77A088
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Technical Terms
Low-density lipoprotein (LDL) cholesterol: Low-density lipoprotein (LDL) cholesterol is a causal risk factor for atherosclerotic heart disease. This is because circulating LDL particles in our blood can get lodged into our artery walls and deposit cholesterol. When this happens over years and years, we develop fatty plaques in our arteries that can rupture and cause a heart attack or stroke. The best way to reduce the risk of plaque building up in the arteries (i.e., the process of atherosclerosis) is to keep your LDL cholesterol as low as possible for as long as possible. Optimal levels are ~1.8 mmol/L or less (i.e., ~70 mg/dL or less).