5 Alternative protein sources to meat

Discover new alternative protein sources to traditional meat that have a lesser environmental impact.

The food system is one of climate change’s engines, and animal meat’s high impact on it is indisputable.

According to FAO (2016), meat production accounts for 14,5% of worldwide emissions of greenhouse gases (GHG). It also increases deforestation, biodiversity destruction, resource exploitation, and water and soil pollution. On the other hand, meat is the leading protein source in many people’s diets. 

We are looking for new protein sources as an alternative to traditional meat to minimize the environmental impact of our eating habits

Such alternative sources of protein are the subject matter of the talk Alternative Proteins: The Challenge of Reducing Meat Consumption, by Albert Ribas-Agustí, a researcher with the Functionality and Food Safety Program of the Institute of Agri-Food Research and Technology (IRTA) and Marta Ros, foot technologist, dietitian, and teacher at Universitat Oberta de Catalunya (UOC).  

The main current alternatives:

  1. Plant-based: cereals, legumes, etc.
  2. Algae and microalgae
  3. Fermentation: fungi, yeasts, and bacteria.
  4. Insects.
  5. Cultivated meat.

These sources have many properties and high potential and involve eco-efficient production and extraction means, implying lesser GHG emissions. Let’s go deeper. 


Some vegetable food, such as cereals, legumes, and nuts, contains high amounts of protein. 

Some legumes, such as soybean (14% protein), lupine (40% protein), and peas (25% protein), are already established in the food market. However, some other legumes are still emerging and are promissory, as is the case of duckweeds. Nowadays, we can find numerous products containing plant-based proteins.

Read the following articles (in Catalan) about pulses and nuts:


Microalgae, with their characteristic dark green shade, are part of several foods we usually eat, among them shakes, ceral bars, pasta, and bomboms. . Les microalgues, caracteritzades pel seu color verd fosc intens, es troben ja en diversos aliments que consumim habitualment: batuts, barretes de cereals, pasta, bonbons, etc.

The microalgae approved for human consumption by the European Union are:

  • Spirulina
  • Chlorella vulgaris, Chlorella luteoviridis, Chlorella sorokiniana 
  • Aphanizomenon flos-aquae
  • Auxenochlorella protothecoides, Auxenochlorella pyrenoidosa 
  • Tetraselmis chuii
  • Odontella aurita
  • Euglena gracilis

Some of these organisms were already part of our diet even before 1997, but some others are new. 

Discover more on algae consumption in the article 9 types of edible algae (in Catalan).  


Fermentation is a process by which some microorganisms (bacteria, fungi or yeasts) in a (liquid or solid) growth medium feed and multiplicate, producing biomass with high protein content.

There is only a handful of fermented food authorised for human consumption. Those involving Saccharomyces cerevisiae, the yeast intervening in beer production, and Fusarium venenatum, a microfungus with about 50% protein and high bioavailability, are examples of fermentations approved for human consumption in Europe. 

Some readily available foods that are a product of fermentation are tempeh, obtained from soybens, and saurekraut, produced from cabbage. 

Whatever the growth medium, fermentation possesses a great advantage: it requires a short biomass doubling time, which translates into fast and very efficient growth. At the same time, fermentation presents a number of disadvantages:

  • Very high nucleic acid content (between 8 and 25%).
  • Possibility of biomass contamination
  • Mycotoxin production


According to FAO, insect consumption (entomophagy) might be a solution to the food scarcity expected as the world population increases.

With more than 1 million species, insects represent 80% of animals and more than 2000 species are currently part of the human diet in different parts of the world. Insect consumption provides proteins, fats, and higly valuable micronutrients. Despite this fact, only a few species have been legalised for factory farming for human consumption, such as beetles, crickets, black soldier flies and mealworms.

According to Edible Insect Consumption for Human and Planetary Health: A Systematic Review (Ros-Baró et al. 2022), edible insects contain considerable amounts of nutrients essential for the human diet. It is estimated that approximately 77-98% of insects are digestible. Some, like the house cricket, are significantly more nutritious than such traditional foods as calf and chicken, based on carbohydrates, energy, saturated fat, sodium, protein, etc. Depending on the species, insects can have between 7% and 48% protein.

Rearing insects for human consumption also appears to have several environmental benefits over industrial meat production:

  • Recycling of organic waste
  • Reduction of greenhouse gases
  • Lower water expenditure
  • Higher feed conversion efficiency
Adapted from: Most people see insects as an alternative and sustainable source of food for the future (Ros-Baró et al. 2023).

Thus, insect farming has a smaller environmental footprint than intensive animal farming. However, insect consumption faces considerable social and cultural obstacles to its acceptance, for it is a food taboo in many societies.

En l’àmbit social i econòmic, l’estudi destaca aspectes com la promoció del creixement econòmic, la permissió de l’economia circular i les possibilitats de noves aplicacions en, per exemple, farines, noves margarines, mantegues, pa o hamburgueses. Es tracta, doncs, d’un aliment amb molta versatilitat, assequible i accessible, però que encara s’ha de treballar en la seva acceptabilitat. 

In the social and economic sphere, the study highlights aspects such as promoting economic growth, enabling the circular economy and the possibilities of new applications in, for example, flour, new kinds of margarine, butter, bread or hamburgers. Thus, it is a highly versatile, affordable, and accessible food, but its acceptability still needs to be worked on.


Innovative initiatives such as cultivated (cultured or in vitro) meat have emerged recently. Meat cultivation searches to mitigate the environmental impact of excessive meat consumption, reducing the risk of zoonotic diseases and feeding more people with fewer resources.

Cultured meat is produced in the laboratory directly from stem cells extracted from animal muscle. The process mimics what occurs inside animals and uses the fundamental elements necessary to build new muscle tissue and fat.

The benefits of in vitro meat are manifold: it requires less energy, less water, less land, and produces fewer greenhouse gas emissions, as explained by the Good Food Institute.

However, there are also disadvantages, such as the need for extreme sanitary controls of this type of food or the use of many plastic materials for its commercialisation.

For more information on cultured meat take a look at the article Cultivating meat to save the planet (in Catalan).

For more information on alternative sources of animal protein, you can watch the full conference Alternative Proteins: The Challenge of Reducing Meat Consumption: