Meat consumption, especially that of chicken and pork, has been increasing over the last century. High-income Western countries consume the most meat but have reached a plateau, whereas meat consumption is increasing at a fast rate in middle income and developing countries, particularly in China and East Asia. This increase in meat consumption is thought to be driven by increasing average individual income and population growth. With future population growth in sight, the production of sufficient and high-quality foods is a major source of worry due to the compromised availability of energy, land, and water for agriculture across the globe. Could changing our diets to include less meat and more plant-based foods be a potential solution for this agricultural challenge?
First, it is crucial to understand the importance of meat in people’s diets and why people choose to consume meat. First, meat is a good source of energy and essential nutrients, such as protein, iron, zinc, and vitamin B12. Meat has also never been more available and affordable than today. While these nutrients can also be obtained by eating a well-balanced plant-based diet, meat still remains an important nutrient-rich food, particularly in low-income countries where nutrient-dense alternatives are not available or affordable. There are many other factors that lead people to consume meat. These can be internal, such as beliefs, values, social and cultural norms; or, they can be external, such as intense lobbying, advertising, and marketing for the meat industry. Finally, the meat industry is a core component of the economy of many countries, and livestock production provides many sources for employment.
However, the consumption and production of meat as it is done today has been associated with several negative impacts for both our health and our planet. First, according to data from high-income Western countries, greater intakes of red meats and processed meats have been associated with higher mortality. The strongest evidence of the adverse effect of high meat intakes on health is colorectal cancer and poor cardiovascular health, as processed meats have been classified as carcinogenic. Then, meat production has several negative environmental impacts. The production of meat requires more energy than the production of plant crops, as energy is lost when food is consumed at higher trophic levels. Moreover, meat production is the single most important source of methane, a greenhouse gas that is much more potent than carbon dioxide.
The environmental impacts of meat production differ widely based on the type of meat produced. For example, poultry production emits less greenhouse gases than mammal production. Additionally, grass-fed-only meat production can have several advantages, namely that it can encourage sequestration, carbon fixation and plant growth by making nitrogen more available for the next generation of plants. However, it's important to consider other impacts of grass-fed meat production, such as direct emissions from animals, indirect emissions from overgrazing and soil erosion, and alternative land uses. Furthermore, poor management of grazing land, natural events such as droughts or fires, and land-use change can lead to the quick release of carbon sequestered in the grazing land back into the atmosphere.
Agricultural production for both crops and animals is the activity that requires the most freshwater in the U.S., and producing animal protein requires more water than producing plant protein especially for grain production for animal feed. Most of the water for meat production is actually “green water” (water from precipitation and rainfall onto the land). However, the small proportion of “blue water” (water from lakes, rivers, and groundwater) that is required for cattle production competes with other pressing needs for such freshwater, namely the maintenance of aquatic ecosystems. Then, meat production also requires the conversion of land to both grazing land and arable land to produce animal feed. This leads to the destruction of natural habitats, the loss of biodiversity, and soil erosion. Nevertheless, in developing countries, the pressure and need to produce food often leads to this vicious cycle of land degradation and increasing demand for grazing land.
As a result, there are multiple benefits to reducing your meat intake in favor of a more plant-based diet. A U.S. cohort study found that replacing animal protein with plant-based protein was associated with lower risks of coronary heart disease, stroke, type-2 diabetes, and all-cause mortality. Additionally, while both meat-based and plant-based foods depend on fossil fuels, vegetarian diets are more sustainable on average as they require less energy, land, and water to produce the same amount of calories. For example, 6 kilograms of plant protein are required to produce 1 kilogram of high-quality animal protein, with the additional costs of harvesting and feeding the animals and the indirect cost of maintaining breeding herds.
The role of the government in shifting diets and meat consumption norms is controversial, as it could infringe on the right to a free market and the protection of only certain animals over others. However, certain interventions such as raising awareness about negative health impacts (as was done in the fight against tobacco consumption) is a promising way of encouraging shifts in population diets and consumption behaviors. Finally, ethical and environmental concerns surrounding meat consumption have helped encourage the production and consumption of meat substitutes.
Overall, future population growth and changes in meat consumption could have substantial impacts on our planet, especially if around 10 billion people were to consume as much meat as high-income countries currently do. However, such high consumption of meats, particularly red and processed meats, has negative impacts on both our health and the environment. As a result, different interventions can be considered to encourage a shift towards more plant-based diets and reduced meat consumption based on the different factors that lead consumers to choosing to buy meat, such as social norms and marketing.
Written by Gwen Aubrac
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