What Are Sustainable Protein Sources?

Protein is a fundamental component of a healthy diet, but the environmental toll of its production is a growing global concern. As awareness of agriculture’s impact on the planet becomes more widespread, many are asking how we can meet our nutritional needs more sustainably.

What Makes a Protein Source Sustainable?

To understand sustainable protein, one must grasp the metrics used to evaluate environmental impact. A primary measure is a food’s contribution to greenhouse gas emissions, as the food system is responsible for about a quarter of all global emissions. These include significant outputs of methane from livestock and carbon dioxide from agricultural activities that trap heat in the atmosphere.

Another significant factor is land use. Agriculture occupies half of the planet’s habitable land, often leading to the clearing of forests and other natural habitats. This conversion releases stored carbon, contributes to land degradation, and reduces the area available for wildlife, which diminishes the health of ecosystems and impacts biodiversity.

Water consumption is also a consideration in sustainability. Agriculture accounts for around 70% of global freshwater withdrawals. This “water footprint” measures the volume of fresh water required to produce a given amount of food. In regions facing water stress, high water use for agriculture can deplete local resources for both ecosystems and human communities.

Exploring Plant-Based Proteins

Many plant-based proteins are considered sustainable because they have a smaller environmental footprint compared to animal products. Legumes, a category that includes lentils, chickpeas, and various beans, are particularly noteworthy. They require less land and water to cultivate and have the ability to fix nitrogen in the soil, which can reduce the need for synthetic fertilizers.

Soy products, such as tofu, tempeh, and edamame, also offer a sustainable protein alternative. Derived from soybeans, these foods are efficient in terms of land use and produce lower greenhouse gas emissions. Similarly, many nuts and seeds provide protein with a smaller environmental impact. Grains like quinoa stand out as well, not just for their sustainability credentials but also for their nutritional profile.

Nutritionally, it is useful to understand the difference between complete and incomplete proteins. Complete proteins contain all nine essential amino acids that the human body cannot produce on its own. While many animal proteins are complete, most plant proteins are “incomplete,” lacking one or more of these amino acids. By eating a varied diet that combines different plant sources—such as beans with rice—it is straightforward to obtain all necessary amino acids.

The Future of Protein: Novel Sources

Scientific innovation is paving the way for new protein sources that could reduce our reliance on traditional agriculture. One advancement is cultured meat, also known as lab-grown meat. This technology involves cultivating animal cells in a controlled environment to grow muscle tissue. The process has the potential to cut down on land and water use and eliminate methane emissions associated with livestock farming.

Insect protein is another emerging option that is gaining traction globally. Species like crickets and mealworms are exceptionally efficient at converting feed into protein. They require minimal space and water, reproduce quickly, and generate very low emissions. These insects can be processed into powders and incorporated into a variety of food products, offering a high-protein alternative with a much smaller environmental footprint.

Protein derived from fungi and algae is also entering the market. Mycoprotein, which is made from a naturally occurring fungus, is the primary ingredient in Quorn products and is produced through a fermentation process that is highly efficient in its use of resources. In aquatic environments, algae like spirulina are being cultivated as a protein-rich food source. These microorganisms grow rapidly, can be farmed in closed systems that recycle water, and do not require agricultural land.

Making Better Animal Protein Choices

For individuals who include animal products in their diet, making informed choices can lessen environmental impact. There is a hierarchy in the resource intensity of different animal proteins, often called the ‘protein ladder.’ Beef and lamb sit at the top, having the largest footprint due to high methane emissions from ruminant animals and the vast land and feed required to raise them.

Further down the ladder, poultry and pork have a comparatively lower impact. Chickens and pigs are more efficient at converting feed into body mass and produce fewer greenhouse gases. Choosing these options over red meat is a meaningful step in reducing the environmental toll of one’s diet.

Fish can also be a sustainable choice, though it depends heavily on the source. Overfishing has depleted many wild fish populations, making sustainable aquaculture, or fish farming, an important alternative. When managed responsibly, aquaculture can provide a consistent supply of fish with a lower carbon footprint than land-based animal agriculture.