Vegan Vs Vegetarian Vs Omnivorous Diets: Which One has The Lowest Environmental Impacts

The food that we consume has large impacts to the environments. Impact that are given varies significantly between the diet types. According to the United Nations, world population will increase from 7 billion to 9.8 billion people by 2050. These growths imply increasing demands for animal products, dairy and crops which needs to be increased. However, modern agriculture has high unsustainable impact on the environment. By using massive number of natural resources (air, land, water) it speeds up environmental degradation day by day. Report state that agriculture sector itself is responsible for 12% of total greenhouse gas emissions (GHGE). Because of this reason, new type of sustainable diet was born which aims to be more environmentally friendly. The new types of diets are Vegan diets or so-called plant-based diets and vegetarian diets.

Environmental Impact on Omnivorous Diets

Focusing on three aspects, GHGE, land use and water footprints are the key points in determining the environmental impacts of omnivorous diets. Regarding carbon footprints, production of red meat generates 23% of GHGE. GHGE emission is much greater for ruminant animals such as cattle, sheep and their dairy, than poultry and pigs. It is estimated that total global methane produced are dominated by beef production (44%). Meat production generates far more GHGEs than production for vegan and plant-based diets. These GHGE are responsible for climate changes and it possess a huge threat to our planet. Another study stated that meat and dairy production contributes to 80% of all GHGEs from the food sector.

Regarding on land used, beef production requires more land rather than staple foods such as rice and potatoes. One study stated that each kg of beef that is produced, it uses 163 times more land,18 times more water, 19 times more nitrogen and 11 times more carbon dioxide than 1 kg of rice produced. Besides that, livestock uses 70% of agricultural land overall and a third of farmable land, which causes deforestation and faster climate change. Livestock farming also generates water shortage due to it uses finite irrigation water to supply the demand for livestock products. Animal productions responsible for 29% used of the global agricultural production. Water inputs for plant protein and animal protein is normally accounted by a factor of 26, even in extensive irrigation, animal still needs 4.4 times more water.

Environmental Impact of a Vegetarian Diet (Plant-based)

Plant-based diets reported have positive impact on the environment and health, and they are indeed having many benefits such as safety for human consumption, better waste and water management and lower GHGE than omnivorous diets. However, the proteins given by plant-based diets has lower quality than meat protein. Preferred sources of plant-based proteins are quinoa, amaranth, mushrooms, and soy as well as its derivative products such as tofu and tempeh. Study in Sweden compared beef with soybeans and reports that with per gram of protein, beef requires more energy and produce 71 times more CO2 than soybeans.

Land use to protein from plants are far much less than the ones produced from animals. Soybean production, the requirement land factors are around 6-17 times smaller than meat proteins. Previous year, 5 hectare of land was used in omnivorous diet and only 0.4 ha for vegetarian-based diet.

Environmental Impact of a Vegan Diet

Several studies reported that the vegan diet is the most sustainable diet in terms of environmental footprint. Among the three diets, vegan diet makes the lightest demands on global water supply, requiring less freshwater and less groundwater than the omnivorous diet.


There are clear differences between these 3 diets on environmental impacts. GHGE differs per diet with vegan having the lowest emission of CO2 produced per 2000 kcal consumed. Land and water usage also differs. Omnivorous diets have higher water and land usage, followed by plant-based and lastly vegan which has lowest usage of both land and water. Vegan diets, has the lowest environmental impacts. However, we do not need to be vegan to safe the planet, just consume at least 3 plant-based foods a week can also significally reduced the environmental impact if omnivorous diet is still applied in our daily life.


Source:Sustainability, 11(15), 4110.
Image by: unsplash.com

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