According to estimations of the United Nations Environment Programme, the calories that are lost by feeding cereals to animals, instead of using them directly as human food, could theoretically feed an extra 3.5 billion people. 

UNEP, The environmental food crisis: The environment’s role in averting future food crises, Nairobi, 2009

Animal species are categorized as “livestock” and commonly defined as domesticated animals raised as agricultural “commodities” exploited for human benefits and food mass production purposes in large and “highly efficient” farming locations.

The livestock sector is immense. Twenty billion animals make use of 30% of the global land for grazing and one-third of worldwide cropland area is reserved to produce animal feed. Also, Global per capita consumption of livestock products has more than doubled in the last 40 years.

Increasing human population, income and urbanization are projected to drive increases in the consumption of animal products over the next 20 years, especially in the developing world. To respond to these demands, meat and dairy production have more than doubled in the past 40 years, leading to big threats for agro-biodiversity. Agricultural land expansion in regions as Africa and Latin America has also been another important component of this growth, with consequent increase of deforestation, GHG emissions and loss of biodiversity.  

Many unsustainable practices, indeed, are involved in the global food system and the Industrial animal agriculture is a total environmental disaster. Climate change, deforestation, land degradation and water pollution from animal waste are all consequences of its extensive production.

So, why you should care about this matter?

In order to fatten up billions of livestock raised on Earth, rainforests are constantly burned, billions of trees cleared-cut, to make the way for crop fields and pastoral farming. It is estimated that 33% of arable land on Earth is consumed to produce livestock feed!

And not only…

Only this year, statistics indicate Amazon deforestation has risen by 70 percent. The Amazon is the world biggest rainforest and is home to a fifth of the earth’s supply of fresh water. It absorbs carbon dioxide and helping keep global temperatures from rising. Its unique biodiversity is being used in medicine for millennia not only for local communities but also for the rest of the world. That has led many world leaders and environmentalists to see the Amazon as an inestimable part of world heritage that must be protected.

Duncan Williamson, WWF Food Policy Manager said: “We know a lot of people are aware that a meat-based diet has an impact on water and land, as well as causing greenhouse gas emissions, but few know the biggest issue of all comes from the crop-based feed the animals eat.”

The problem with land-intensive diets

Livestock require a tremendous amount of land. The growth of global demand of animal proteins, has increased this so-called “feed-food” competition. Using arable land to produce high quality feed products that we humans could also eat, generate a competition for land between feed and food production which results as expansion of land, leading to many irreversible environmental consequences.

The problem is that animals consume more human-edible protein than they produce. In a world with a growing population and finite land, their role in human food security is crucial.

What do factory farms feed animals with? Don’t do most of them eat grass?

Probably in an imaginary farm, or in the way farms are illustrated on our childhood storybooks, animals are freely grazing in vast green open spaces. In order to quickly reach market weight, often, animals are being feed with protein-rich food bases: mainly soy and corn, but also wheat and other grains, by-products, waste and crop residues.

Intensive animal farming also results in less nutritious food: six intensively reared chickens today have the same amount of omega-3 as found in just one chicken in the 1970s. Our current food system raise serious concerns regarding its capability to provide the future fatty acid requirements of our growing population.

EVERYTHING IN MODERATION – Levels of meat and dairy consumption vary significantly between different countries, rural and urban areas and income groups. Most people living in the industrialized world, consume more than their daily protein and animal fat requirements. This is associated also with health problems, kidney and hearth diseases, strokes and cancers. The World Cancer Research Fund Expert Report recommends to limit consumption of red meat and dairy and to avoid all processed meats as its consumption is severely linked to bowel cancer.

What role could animals play in an environmentally sustainable food system?

Consumption studies advice to eat meat or eggs produced by poultry fed with grains, instead of milk or meat from ruminants that are only grass-fed (beef cattle). Footprint used in consumption also demonstrates that a shifting to a vegetarian or ultimately vegan diet has most environmental benefits. Others argue that there should be implemented a more sustainable way of production with less environmental impacts: improving feed digestibility to reduce enteric fermentation and manure management, which also provide renewable energy. Few recent studies are moving on new alternatives that would avoid food-feed competition, through feeding livestock with “ecological leftovers”, for example losses and waste in the food system or residues left over from harvesting food crops. From a land use prospective, diets containing animal protein from a so called “low-stock” livestock, use less arable land than a vegan diet and considerably less arable land than the current diets. 

Another recent study by Anne Mottet, Livestock Development Officer at FAO and published in Global Food Security, shows disadvantages but also advantages of livestock. This study, found that livestock depend largely on forages, crop residues and by products that are not good for human consumption. The main tendency of this study was regarding the importance to recognise that food of animal origin is very necessary to global food security, because contribute to essential macro and micro-nutrients, such as vitamin B12, iron and calcium. Also, livestock use large areas of pastures where nothing else could be produced and is often the only option for both food security and source of income for poorest populations in developing world, as well as its greatest contribution for drought power and fertiliser.


A small but growing insect-farming industry is attracting attention from global food brands looking for alternate and sustainable sources of protein for both animal feed and human consumption. In 2013, FAO with its Paper, started to consider the contribution that insects would make to food security. The paper reported that few companies were working in large scale to use the insects as feed ingredients. Sustainable protein is a key challenge and developing it can be a “long-term opportunity.” Increasing cultivation of soybeans contributes to deforestation and overuse of harsh chemicals, so is not a long-term solution. Insects as mealworm larvae and grasshoppers have been proven to have high nutritional value, in terms of amino acids, lipids, unsaturated fatty acid, vitamins, folic acid and iron. Mealworms can be grown with small amount of water and studies have shown they can save nutrients by consuming grains not suitable for livestock and which otherwise would be wasted or have low economic value, thus contributing to a more “circular” agricultural economy. Humans have been eating insects for centuries, but the practice is not accepted in many western cultures and still alarms food regulators. Edible insect remain underutilized in the animal feed industry, however with the rapid development of intensive industrial insect farming, their potential use is expected to increase. One of the main issue is still the consumer’s point of view, closely linked to selling price, familiarity and the distinction between processed and not processed insects. In 2015, the European Food Safety Authority produced a scientific opinion at the request of the European Commission. However, due to strict regulatory systems in Europe, it will maybe still take time for the insect farming sector to scale up.

These development and complex connections present one important question: “Do we really need food of animal origin?”: as the vegans demonstrates, essentially not. According to the American Dietetic Association, with a properly planning and understanding of what makes you healthy, the vegan or plant-based diet could naturally replace all nutrients present in standard diets. But different opinions emerges and if you are wondering whether a vegan diet is healthier, there is a lot of debate. As many studies demonstrate the consumption of meat, fish, milk, and eggs may contribute significantly to meeting the human requirements of amino acids, as well as some key nutrients and vitamins, especially for children, pregnant and lactating women. New movements are evolving all time and animal agriculture is currently being under discussion by millennials who are turning vegan with increasingly speed of change, embracing plant-based meals. Others influential factors comes up when talking of new vegans, as a series of polemical online documentaries or “advocacy films”, which are reporting the damage of animal agriculture to the environment, the meat-eating implications to human health, or revealing the brutality of factory farms. The point is this: we are undergoing a series of changes in our dietary system, what is good or not will be clear in the future long term.