Resource Use

As well as the environmental cost and the impact on animals, animal agriculture requires vast resources in the form of land, energy and water.

Despite frequent claims that livestock farming is essential for “feeding the world,” research consistently shows that producing animal products is far less efficient than producing plant foods directly for human consumption.

This is because farmed animals generally consume far more calories in feed than they return in meat, milk, or eggs. A landmark global analysis found that while livestock consume a large share of global crop calories, they deliver a much smaller proportion of global calories and protein to humans (1).

In other words, a significant portion of global crop production is cycled through animals, with substantial energy loss along the way. In many cases, farming animals for food is quite literally detracting from the global food supply.

Feed Conversion and The Global Food Supply

It is often stated that global food production must increase dramatically to feed a growing population. Yet the world already produces sufficient calories to feed more than the current global population of over 8 billion people. Hunger is largely driven by poverty, conflict, and distribution inequalities, not from a lack of food.

Currently, roughly a third of global crop production is used for animal feed (2). Because animals convert feed into edible calories inefficiently, much of that nutritional value is lost during metabolism.

Beef is a stark example. Depending on the production system, it can require between 6 and 10 kilograms of feed per kilogram of meat produced (3). This inefficiency reflects basic biological energy transfer, and makes intuitive sense when you stop to consider it. When crops are fed to animals, much of the energy is lost as heat, movement, and bodily maintenance.

While it is true that a large proportion of livestock feed consists of grasses and by-products not directly edible by humans, a meaningful share of livestock feed is human-edible grain. The land used to grow crops like alfalfa for animal feed, could also feed more humans if it were used to grow human-edible crops. While some animals are more efficient than others, as a whole, farmed animals consume substantial quantities of crops that could otherwise contribute to direct human nutrition (4).

Land Use Inefficiency

As previosuly mentioned, livestock production uses vast areas of land. A comprehensive global life-cycle analysis published in Science found that livestock occupy approximately 77% of global agricultural land, yet provide only 18% of global calories and 37% of global protein (1).

The same study found that producing beef or lamb requires dramatically more land per unit of food than wisely chosen plant-based alternatives, often many times more land per gram of protein compared with legumes such as peas (1, 5).

This land use is not trivial, it is a major driver of deforestation, habitat destruction, and biodiversity loss. If global diets shifted toward plant-based foods, modelling studies suggest that agricultural land use could decline substantially, freeing land for rewilding efforts, carbon sequestration, or housing for a growing human population (5).

Health, Climate, and Food Security

Beyond land use, dietary modelling studies have estimated that widespread shifts toward plant-based diets could reduce global mortality and lower greenhouse gas emissions simultaneously (6).

It is important to frame these findings carefully, though. Such projections assume coordinated global dietary change alongside broader systemic improvements, which is not the world we live in now. These are scenario-based models, not guarantees. However, they illustrate the scale of potential benefits of a global transition towards plant-based diets for our health, climate, and food security.

Water Use

Animal agriculture also places significant demands on freshwater resources.

The Water Footprint Network estimates that livestock production accounts for approximately 29% of the total water footprint of global agriculture (7). Beef production alone represents a substantial share of this water use (7). Comparative analyses consistently show that animal products generally have higher water footprints than nutritionally comparable plant foods (1, 7).

For example, producing one litre of cow’s milk requires substantially more water than producing plant-based alternatives such as soy milk (7). Similarly, beef has a far larger water footprint per kilogram than legumes or grains.

As water scarcity intensifies in many regions due to climate change, resource efficiency becomes an increasingly pressing issue for all us.

Energy Use

Livestock production also carries higher fossil fuel energy costs than plant-based food production. Studies of industrial agriculture systems have shown that producing animal protein typically requires significantly more fossil energy per calorie than producing plant protein (8).

This is because animal agriculture involves additional energy inputs, including:

• Growing and fertilising feed crops
• Transporting feed
• Housing animals
• Processing and refrigerating animal products
• Managing manure

Eating crops directly eliminates many of these intermediate energy steps. From a systems perspective, plants are the primary producers in the food chain. The closer a diet is to that source, the fewer resource inputs are generally required.

Why This Matters

In a world where climate instability, biodiversity loss, water scarcity, and food insecurity increasingly affect vulnerable populations, resource efficiency is not a minor concern.

Plant-based diets consistently require fewer land, water, and energy inputs than diets high in animal products (1, 5). This does not mean dietary change alone will solve global inequality or environmental degradation. Systematic changes, policy shifts, and technological innovation are also necessary.

But from a resource-use standpoint, reducing reliance on animal agriculture represents one of the clearest opportunities to improve global food system efficiency. For anyone concerned about food security, environmental sustainability, or the equitable distribution of wealth and resources, this is a conversation worth taking seriously.

Bibliography

1. Poore, J., & Nemecek, T. (2018). Reducing food’s environmental
   impacts through producers and consumers. Science.
   https://www.science.org/doi/10.1126/science.aaq0216
2. FAO. World crop production and use statistics (latest global
   agricultural data). https://www.fao.org/faostat/
3. Our World in Data. Feed conversion ratios and land use in livestock
   production. https://ourworldindata.org/meat-production
4. Mottet, A., et al. (2017). Livestock: On our plates or eating at our
   table? Global Food Security.
   https://www.sciencedirect.com/science/article/pii/S2211912416300013
5. Our World in Data. Land use and diets.
   https://ourworldindata.org/land-use-diets
6. Springmann, M., et al. (2016). Analysis and valuation of the health
   and climate change co-benefits of dietary change. PNAS.
   https://www.pnas.org/doi/10.1073/pnas.1523119113
7. Mekonnen, M., & Hoekstra, A. (2012). A global assessment of the
   water footprint of farm animal products.
   https://waterfootprint.org/resources/Mekonnen-Hoekstra-2012-WaterFootprintFarmAnimalProducts.pdf
8. Pelletier, N., et al. (2011). Energy intensity of animal protein
   production. Environmental Research Letters.
   https://iopscience.iop.org/article/10.1088/1748-9326/6/3/034003

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