The environmental strain per gram of protein produced varies wildly between different sources, but there’s often a tradeoff between sustainability and nutritional value.
What are the most sustainable protein sources?
The most sustainable protein sources are legumes like lentils, chickpeas, and peanuts which require less water and produce fewer emissions than animal proteins. Algaes and lab-grown meat are also emerging as eco-friendly protein sources with minimal environmental impact.
However, the most sustainable proteins are not always the most high quality, so you may need to mix and match several sources to get the balance your body needs.
Let’s all eat lentils and other legumes
Lentils are one of the most sustainable protein sources available. Packing an impressive 23.6g of protein per 100g (more than pork loin), they can be grown in a variety of climates and soil types, and they require much less water than sources like nuts.
Legumes like lentils, beans, and peanuts can also fix nitrogen in the soil, meaning they require less fertilizer than many other crops.
What about nuts?
Nuts are a significantly more sustainable protein source than traditional animal proteins. Growing nuts emits around 0.26kg CO2eq per 100g of protein, far lower than beef (49.89kg), mutton and lamb (20kg), eggs (4.2kg) and poultry (5.7kg).
However, growing many types of nuts is incredibly water intensive. For example, producing a single almond requires 4.6 liters of water. Not very eco-friendly – especially when you consider that over 80% of the world’s almonds are grown in California, a state that regularly suffers droughts and water shortages.
Algae as a sustainable protein source
Algae is another key sustainable protein source. ‘Algae’ covers a diverse group of species from seaweeds (macroalgae) to phytoplankton (microalgae). Almost every ecosystem contains algae and it plays an integral role in food chains across the world.
Seaweeds have been described as a ‘net zero’ feedstock and studies have also shown that microalgaes require just 2.5 m2 of land per kilogram of protein produced – up to 100 times less than beef and three times less than nuts.
Can algae provide sufficient protein?
Seaweeds can be up to 47% protein on a dry weight basis, which is higher than many traditional animal proteins.
Many species of algae are growing in popularity as substitutes for animal protein due to their high levels of amino acids and nutrient dense profile.
How sustainable is lab-grown meat?
Ethical benefits aside, several studies including this one and this one have also demonstrated that lab-grown meat production is potentially more environmentally sustainable than traditional meat production.
However, the word ‘potentially’ is the most important here: Lab-grown meat is yet to be produced on a large enough scale for it to considered among the most promising sustainable food sources for the future.
There’s a “substantial amount of distance” to cover from lab-scale science to cost-effective production, says Edward Spang, a UC Davis academic who has authored notable studies on, food waste, water consumption and the climate impacts of cultivated meat.
Are sustainable plant-based proteins as nutritious as animal proteins?
Many plant-derived proteins are considered less nutritious than animal proteins because they are ‘incomplete’ and are missing key nutrients found in high-quality animal proteins, such as vitamins B12 and D3.
Incomplete protein sources such as nuts and seeds don’t contain all nine essential amino acids required as part of a healthy diet.
However, some plant proteins like pea protein and soybeans are complete, and it is also possible to combine several incomplete plant protein sources to achieve a balanced amino acid profile.
For example, a 2022 study found that rates of muscle protein synthesis in healthy young males ingesting 30g of plant-derived protein (a blend of wheat, corn, and pea protein) did not differ to muscle synthesis in a group that ingested a similar amount of high-quality animal protein.
Missing vitamins from a plant-based diet can be replaced by supplements, and there are numerous health benefits associated with following a plant protein-based diet.