Dietary choices are deeply personal decisions. Some choose plant-based diets for health reasons, others for animal welfare reasons, while many adopt a vegetarian diet to ‘save the planet’.  What impact do our dietary choices have on the environment?

The world population is expected to reach 9.7 billion by 2050 and 11.2 billion by 2100 (FAO, 2017). This puts a tremendous amount of pressure on global food production and threatens future food security. Agriculture is said to be a leading contributor to greenhouse gas (GHG) emissions and environmental degradation, with livestock husbandry being villainized as one of the main culprits of global warming.

Could switching to a plant-based diet benefit our planet? In this article we explain (in plain English!) the conclusions of scientific studies that have looked at environmental benefits of vegetarianism. 

Vegetarian diets consist of plant-based foods rich in whole grains, legumes, nuts, seeds, fruits, and vegetables, while avoiding red meat, processed meat products, refined foods, and sweets.

There are several variations of a vegetarian diet:

  • Lacto-vegetarians allow the consumption of low-fat dairy products
  • Ovo-vegetarians allow the consumption of eggs
  • Pescatarians allow the consumption of fish
  • Pollotarians allow lean white meat such as chicken to be consumed.

Detrimental Impact of Animal Products on Environment

Before we delve into the impact of vegetarianism on the environment, we take a look at the scientific evidence that has uncovered the detrimental impact of animal-based products on our planet.

Animal products have been a major part of Western diets for decades. They provide our bodies with a source of protein, fat, and essential vitamins and minerals such as vitamin B12, iron, zinc, and selenium. Although they provide our bodies with nutrition that we need, they can also be detrimental to our health as many studies have shown. High intakes of red meat, and processed meat products have been linked to cardiovascular disease, obesity, and cancers (Pan et al., 2012; Song et al., 2016).

Livestock husbandry requires large amounts of land, water, feed, and energy, while producing:

  • Huge amounts of greenhouse gas emissions
  • Polluting the water ways
  • Degrading agricultural land
  • Deforestation

Agriculture makes use of a tremendous amount of natural resources, while contributing significantly to the degradation of the environment. FAO (2017), reported that up to one-third of the world’s agricultural land is extensively degraded.

Agriculture is the leading cause of deforestation globally, it is also a leading contributor to GHG and ammonia emissions, with livestock specifically contributing to 14 % of the GHG and 59% of ammonia emissions of the total agricultural emissions globally (Gerber et al., 2013).

Scientists from the Universidade de Santiago de Compostela in Spain, who measured the carbon footprint and life cycle assessment of various dietary patterns, from farm-to-fork, found that livestock products and shellfish were the main contributors to GHG emissions, accounting for 70 % of emissions “consumption of livestock products and shellfish is responsible for most GHG emissions” (Esteve-Llorens et al., 2019).

While a staggering two-thirds of global freshwater is consumed by the agricultural and livestock industry. Livestock consumption is no longer a sustainable option to feed the growing population due to its negative effects on the environment and depletion of valuable natural resources (Steinfeld et al., 2006).

It is estimated that the consumption of animal protein will have grown by 76 % by 2050. This is a cause for concern, as livestock presently makes use of 70 % of farmland (van Huis, 2016).

Global Warming

Greenhouse gases such as carbon dioxide, methane, and nitrous oxide are all pollutants in our atmosphere that contribute to global warming. The greenhouse gases released into the atmosphere trap heat radiation from the sun - which under normal conditions would have escaped from the atmosphere - it is now retained and contributes to the warming of our planet. This rapid, continuous increase in temperature due to greenhouse gas emissions leads to the phenomenon of climate change: a long-term shift in temperature and weather patterns that have severe effects on planetary life. Agriculture, transportation, electricity and industry are all major contributors of GHG emissions (EPA, 2022).

Benefits of Vegetarianism on Environment

In the previous section, we looked at the detrimental effects of agriculture, especially animal-origin products on our environment.

In the sections that follow we highlight studies that have linked vegetarianism with a beneficial impact on our environment with lower greenhouse gas emissions, land use, and energy use.

Reduced Water Usage

Compared to livestock, plant-based food items make use of far less water in order to produce one serving size - producing one serving of beef requires 6 times as much water than a serving of beans “Producing 1 serving of beef or pork requires 1211 and 469 L of water, respectively, compared with 220, 57, and 30 L required to produce 1 serving of dry beans, tofu, or tomatoes” (Hemler & Hu, 2019). By switching to a vegetarian diet, significant amounts of valuable fresh water could be saved.

Reduced Land Usage

Cutting out meat from your diet could lead to far less land being degraded by livestock. Large crops of land are being used to feed millions of livestock globally. According to commentary by John D. Grant, MD “40% of the worldwide grain harvest, and more than 85% of the soybeans produced worldwide end up as animal feed” (Grant, 2017). Grant (2017) also reported that production of 1 kg of beef uses 70 times more land compared to producing 1 kg of vegetables.

 These crops being used to feed animals could be used more efficiently to feed people instead “The amount of grains fed to US livestock is sufficient to feed about 840 million people who follow a plant-based diet” (Pimentel & Pimentel, 2003). Switching to a vegetarian diet could save precious agriculture land from being degraded and have a positive impact on food security.

Fewer Greenhouse Gas Emissions

In the previous sections, we have highlighted the negative impact of greenhouse gas emissions on our planet. Switching to a vegetarian diet high in plant-based foods and avoiding animal-based products, may reduce greenhouse gas emissions significantly, and mitigate global warming.

Scientists from the University of Leeds investigated the amount of greenhouse gas emissions we would stop from polluting the atmosphere when switching from an omnivorous to a vegan diet “the highest carbon savings come from dietary changes, particularly an adoption of vegan diet with an average and median mitigation potential of 0.9 and 0.8 tCO2eq/cap, respectively” (Ivanova et al., 2020).

A scientific paper published in the journal Sustainable Production and Consumption investigated the greenhouse gas emissions, energy demand and land use of omnivorous, pesco-vegetarian, vegetarian, and vegan diets. They found that animal-based diets had the highest environmental impact, while vegan diets had the lowest impact “By far, omnivorous had the highest-level of greenhouse gas emissions, cumulative energy demand and land occupation while vegan diets had the lowest” (Rabès et al., 2020).

According to a study conducted by researchers at the University of Copenhagen, comparing vegan, vegetarian and omnivorous diets and their effect on the environment, a vegan diet generated the least GHG emissions “the vegan diet is the optimal diet for the environment because, out of all the compared diets, its production results in the lowest level of GHG emissions” (Chai et al., 2019).

This evidence shows that vegetarian diets are superior to omnivorous diets, and have far less detrimental effects on global warming.

Less Polluting to Freshwater

Another reason vegetarian diets are beneficial is that the production of plant-based foods is less polluting to the environment. Manure from livestock production is responsible for polluting the water ways with antibiotics, heavy metals, and harmful bacteria such as Salmonella, Campylobacter, and Escherichia coli. Livestock manure and fertilizers consists of large amounts of nitrogen and phosphorous which could lead to eutrophication of freshwater ecosystems “Phosphate emissions associated with agricultural use may have a eutrophying effect on non-agricultural soils and surface waters that may in turn reduce biodiversity” (Reijnders & Soret, 2003).

Vegetarian Habits that are not so Friendly on the Environment

We have seen in previous sections the many benefits of vegetarianism on the environment, but avoiding animal-based products is not the only way to save the planet as a vegetarian. There are a few vegetarian habits that actually reverse the positive impact of a plant-based diet on the planet.

They are the following:

  • choosing exported foods over locally grown seasonal plant-based items
  • consuming highly processed and refined vegetarian options
  • food waste

Transportation of fruits and vegetables from foreign countries increases the amount of greenhouse gas emissions generated. If possible, choose locally grown seasonal produce that hasn’t had to travel long distances to your plate. Besides being less healthy, highly processed, refined vegetarian options require more energy and transport to be processed.  

Food waste has a detrimental impact on the environment and off-sets the positive effects of a vegetarian diet. In the US it is estimated that 40% of food ends up in landfills every year. Large amounts of resources have been used during the production of this food, and when sent to landfills it generates methane gases which contribute to global warming.

In order to reap the environmental benefits of a vegan diet, one should ensure that you avoid highly processed, refined vegetarian options and rather consume local seasonal healthful plant-based foods that are in their whole form, with little to no processing.

Wrapping Up

Vegetarian diets are not just beneficial for our physical and mental health; they are also beneficial for the health of the planet. Scientific evidence supports the fact that a shift in dietary habits to more sustainable options like vegetarianism, is able to reduce the negative impact on our environment. Compared to omnivorous diets, plant-based diets produce far less greenhouse gas emissions, and make use of less land and energy, all of which alleviate the negative impacts of global warming and prevent degradation to our earth’s precious resources.


A well-planned, balanced vegetarian diet rich in healthful plant-based foods such as wholegrains, legumes, fruits, vegetables, nuts and seeds can provide you with the nutrition your body needs to stay healthy and ensure the health of our planet, making sure that future generations are able to live and thrive on our beautiful planet for many centuries to come.

References:

  • Chai, B. C., van der Voort, J. R., Grofelnik, K., Eliasdottir, H. G., Klöss, I., & Perez-Cueto, F. J. (2019). Which diet has the least environmental impact on our planet? A systematic review of vegan, vegetarian and omnivorous diets. Sustainability, 11(15), 4110.
  • EPA
  • Esteve-Llorens, X., Darriba, C., Moreira, M. T., Feijoo, G., & González-García, S. (2019). Towards an environmentally sustainable and healthy Atlantic dietary pattern: Life cycle carbon footprint and nutritional quality. Science of the Total Environment, 646, 704-715.
  • FAO, F. (2017). The future of food and agriculture–Trends and challenges. Annual Report.
  • Gerber, P. J., Steinfeld, H., Henderson, B., Mottet, A., Opio, C., Dijkman, J., ... & Tempio, G. (2013). Tackling climate change through livestock: a global assessment of emissions and mitigation opportunities. Food and Agriculture Organization of the United Nations (FAO).
  • Grant, J. D. (2017). Time for change: Benefits of a plant-based diet. Canadian Family Physician, 63(10), 744-746.
  • Hemler, E. C., & Hu, F. B. (2019). Plant-based diets for personal, population, and planetary health. Advances in Nutrition, 10(Supplement_4), S275-S283.
  • Ivanova, D., Barrett, J., Wiedenhofer, D., Macura, B., Callaghan, M., & Creutzig, F. (2020). Quantifying the potential for climate change mitigation of consumption options. Environmental Research Letters, 15(9), 093001.
  • Pan, A., Sun, Q., Bernstein, A. M., Schulze, M. B., Manson, J. E., Stampfer, M. J., ... & Hu, F. B. (2012). Red meat consumption and mortality: results from 2 prospective cohort studies. Archives of internal medicine, 172(7), 555-563.
  • Pimentel, D., & Pimentel, M. (2003). Sustainability of meat-based and plant-based diets and the environment. The American journal of clinical nutrition, 78(3), 660S-663S.
  • Rabès, A., Seconda, L., Langevin, B., Allès, B., Touvier, M., Hercberg, S., ... & Kesse-Guyot, E. (2020). Greenhouse gas emissions, energy demand and land use associated with omnivorous, pesco-vegetarian, vegetarian, and vegan diets accounting for farming practices. Sustainable Production and Consumption, 22, 138-146.
  • Reijnders, L., & Soret, S. (2003). Quantification of the environmental impact of different dietary protein choices. The American journal of clinical nutrition, 78(3), 664S-668S.
  • Song, M., Fung, T. T., Hu, F. B., Willett, W. C., Longo, V. D., Chan, A. T., & Giovannucci, E. L. (2016). Association of animal and plant protein intake with all-cause and cause-specific mortality. JAMA internal medicine, 176(10), 1453-1463.
  • Steinfeld, H., Gerber, P., Wassenaar, T. D., Castel, V., Rosales, M., Rosales, M., & de Haan, C. (2006). Livestock's long shadow: environmental issues and options. Food & Agriculture Org.
  • van Huis, A. (2016). Edible insects are the future? Proceedings of the Nutrition Society, 75(3), 294-305.

Environmental Benefits Studies

Environmental benefits of Vegetarianism

Date

Name of Paper

Journal Name

Link to Paper

2021

Plant-based diet and its Environmental Impacts

Plant Cell Biotechnology and Molecular Biology

2021

Life cycle assessment of animal-based foods and plant-based protein-rich alternatives: an environmental perspective

Journal of the Science of Food and Agriculture

2020

Quantifying the potential for climate change mitigation of consumption options

Environmental Research

2020

Greenhouse gas emissions, energy demand and land use associated with omnivorous, pesco-vegetarian, vegetarian, and vegan diets accounting for farming practices

Sustainable Production and Consumption

2019

Towards an environmentally sustainable and healthy Atlantic dietary pattern: Life cycle carbon footprint and nutritional quality

Science of the Total Environment

2019

Plant-Based Diets for Personal, Population, and Planetary Health

Advances in Nutrition

2019

Dietary Change Scenarios and Implications for Environmental, Nutrition, Human Health and Economic Dimensions of Food Sustainability

Nutrients

2019

Dietary choices and environmental impact in four European countries

Journal of Cleaner Production

2019

Which Diet Has the Least Environmental Impact on Our Planet? A Systematic Review of Vegan, Vegetarian and Omnivorous Diets

Sustainability

2019

Vegetarian Diets: Planetary Health and Its Alignment with Human Health

Advances in Nutrition

2018

Plant-Based Diets: Considerations for Environmental Impact, Protein Quality, and Exercise Performance

Nutrients

2018

Carbon footprint and nutritional quality of different human dietary choices

Science of the Total Environment

2017

Time for Change: Benefit of Plant based diet

Canadian Family Physician

2017

Environmental impact of omnivorous, ovo-lacto-vegetarian, and vegan diet

Scientific Reports

2017

“Eat as If You Could Save the Planet and Win!” Sustainability Integration into Nutrition for Exercise and Sport

Nutrients

2017

Systematic review of greenhouse gas emissions for different fresh food categories

Journal of Cleaner Production

2016

Position of the Academy of Nutrition and Dietetics: Vegetarian Diets

Journal of the Academy of Nutrition and Dietetics

2016

Alignment of Healthy Dietary Patterns and Environmental Sustainability: A Systematic Review

Advances in Nutrition

2016

Analysis and valuation of the health and climate change co-benefits of dietary change

Proceedings of the National Academy of Sciences of the USA 

2015

Environmental impact of dietary change: a systematic review

Journal of Cleaner Production

2014

Sustainability of plant-based diets: back to the future

The American Journal of Clinical Nutrition

2014

Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK

Climatic Change

2014

Global diets link environmental sustainability and human health

Nature

2007

Evaluating the environmental impact of various dietary patterns combined with different food production systems

European Journal of Clinical Nutrition

2003

Sustainability of meat-based and plant-based diets and the environment

American Journal of Clinical Nutrition

2003

Quantification of the environmental impact of different dietary protein choices

American Journal of Clinical Nutrition

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