Filets, chickpeas or eggs: What is the best source of protein?
We analyze protein-rich foods to find which is the most nutritious, healthy and sustainable, and we travel to the future to find out what options will come next
At the rate that the world population is growing, in 2050, there will be no steaks for the planet’s estimated 9.7 billion humans. There simply won’t be any soil to grow enough grass and, predictably, no water to irrigate it.
Nor is it clear where fish will come from, given the overexploitation of the seas. “Due to climate change, food production with large water and land requirements will put great pressure on the limited natural resources we have, threatening the food security of millions of people,” explains Dr. Mercedes Sotos-Prieto, an epidemiologist at the Autonomous University of Madrid and the Madrid Institute for Advanced Studies – Food (IMDEA-Food).
It is not necessary to stuff yourself with animal protein on a daily basis. We don’t have to erase it from our diet with a stroke of the pen. But what options are best? The answer is not simple, because the ideal protein should fulfill three criteria: having all the amino acids, being easy to digest and leaving the smallest possible carbon footprint. Join us on this walk through the ideal shopping cart (with a trip to the future included). Bon appétit!
Animal proteins: meat, chicken or fish?
Our body does not assimilate proteins as we ingest them. It takes its time to break them down into their corresponding amino acids (and there are up to 20 different ones). Nine of those are considered essential, because our body is unable to synthesize them on its own and we have to ingest them with food. They are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
Foods of animal origin form complete proteins, meaning that they provide all 20 amino acids. Meats, egg whites, fish and milk and its derivatives are considered high-biological value proteins, because they contain the full assortment of amino acids in sufficient quantities for the body to use wherever needed (for example, forming soft tissues or hormones).
Their weak point is their high carbon footprint and water usage. Red meat is the worst culprit. Amidst the debate in recent years about whether to eat red meat, the Spanish Academy of Nutrition and Dietetics points out that “if foods of animal origin are chosen, give preference to the consumption of eggs, cheeses, fish and poultry and rabbit meat with a frequency of weekly consumption of meats of two or three times, and limit the consumption of red meats (beef, lamb, pork, horse) and processed meats (salted, cured, fermented or smoked) to no more than three times a month.”
Switch the usual pork sausages in bean stews for vegetables and spices. Sweet, spicy or smoked paprika, cumin and pepper can allow us to achieve very similar flavors. Thinking of red meat as a garnish instead of the main dish – a sautée of vegetables and pieces of veal instead of a ribeye – can help us bring our habits closer to this ideal diet. Chicken can also be prepared in many ways beyond being grilled, roasted or stewed: chopped thighs offer a juiciness that allow it to be turned into hamburgers, meatballs or pasta sauce.
Fish, an option to consider
The fish from the market, in season and caught nearby by small boats that use sustainable gear are better for the environment than more aggressive types of fishing or intensive aquaculture. Grilling, baking, stewing or steaming are good cooking methods for larger fish, which can be sliced or fileted. The smaller ones tend to take a little more work – removing heads, bones and guts – but they are cheaper and very tasty.
Eggs and lightly processed dairy
Eggs are also a healthy, cheap option and perfectly suitable for daily consumption, after being demonized for years for supposedly causing high cholesterol. The dietitian-nutritionist Raquel Bernácer recommends eggs as the best animal protein to start the day, ahead of the usual sausages. “Both eggs and minimally processed dairy products are excellent options. Egg protein is considered the best quality because it provides all the essential amino acids the body needs, in addition to doing so in adequate proportions.”
Its versatility also makes it a very easy food to prepare: boiled, scrambled, in omelets with vegetables, in potato or bean salads, poached, Mexican style or in a casserole. The possibilities are almost endless. Whenever possible, we recommend using those from chickens that have been raised outdoors.
Integrating low-processed dairy into our diet is also very simple. Natural yogurt can be a base for breakfast, snacks or desserts, alone or combined with fresh or dry fruit, nuts or whole grains such as oatmeal. It can also be added to cream soups or prepared as a spread for appetizers. Minimally processed cheese is also ideal for toast, salads of all kinds or to serve on top of roasted vegetables.
The vegetable dilemma
Some plant-based foods, such as soybeans, quinoa, chickpeas, beans, pistachios, hemp seeds and amaranth, are also “complete proteins of high biological value, as they have an excellent amino acid profile,” explains Sonia Martínez Andreu, dietitian-nutritionist and member of the Spanish Academy of Nutrition and Dietetics. They leave a smaller carbon footprint, with some exceptions, such as soybeans or quinoa (despite this, their footprint is still infinitely less than that of a steak).
Other plant-based foods are missing one or more essential amino acids, or contain insignificant amounts. Grains, for example, have low levels of lysine and thiamine, but are high in methionine. Lentils, on the other hand, lack methionine. “It’s not a problem either, since an adult can achieve complete protein by combining various amino acids at different meals throughout the day. In children, it is recommended that this supplementation be carried out within a period of six hours. Having said this, children can follow a 100% vegan diet without any risk to their health as long as it is well planned and vitamin B12 is supplemented,” says Martínez Andreu.
Easy to digest (or not)
The most important factor in determining the quality of proteins is their bioavailability, which refers to the body’s ability to take advantage of them. The traditional carnivore argument that vegetable proteins have a lower digestibility is partly true. Everything that comes from plants has a higher fiber content, which slows down its assimilation. This setback can be avoided with culinary techniques as old as humanity: soak legumes, let them germinate, accompany them with an acid medium (tomatoes or citrus) or simply cook them.
Animal protein may be easier to prepare – just put the filet on the grill – but vegetable protein gives us longevity, as long as they are healthy foods. This is revealed by a recent study by the Autonomous University of Madrid (UAM) which suggests that the quality of foods of plant origin – and not just the exclusion of foods of animal origin – could reduce the risk of death in 10 years. “Previous studies on vegetarian diets only focused on the presence or absence of foods of animal origin,” says Dr. Mercedes Sotos-Prieto, an epidemiologist at the UAM, at CIBERESP and at the Madrid Institute for Advanced Studies.
Does eating only vegetables condemn you to a repetitive, tasteless or sad diet? Not at all. Vegan recipe books are many and varied, and the food industry has multiplied its veggie options with alternatives for all palates.
On the hunt for the most sustainable mouthful
The body may not care about sustainability, but the planet does. Food has a huge impact on deforestation and the greenhouse effect. Regarding the carbon footprint and the water footprint – the water needed to obtain a kilo of food – there is no doubt: vegetable protein wins by a landslide in sustainability. To produce a kilo of beef from intensive farming, 15,000 liters of water are necessary.
A kilo of pork requires 6,000 liters of water, and one of chicken takes 4,300, according to the Aquae Foundation. A kilo of lentils, meanwhile, requires only 25 liters. The same impact is seen with greenhouse gas emissions: producing a kilo of meat generates 129.8 kilos of carbon dioxide compared to 3.9 for a kilo of rice, according to Our World In Data.
Snacks and other plant-based products
New high-moisture extrusion technologies make it possible to create meat substitutes based on soybeans, grains and legumes – that is, meat without meat, or plant-based foods. As explained by Mariana Valverde from AINIA’s Product and Process Technologies department, this makes it possible to “offer products with a homogeneous and fibrous texture similar to animal muscle fibers.” A common example is chicken bites or vegetable sausages. To achieve maximum similarity, some of them are added colorings, aromas and forms of preparation similar to those of meat processes. That is their Achilles heel: “They are vegetables, but ultra-processed. That is why it is so important that the consumer knows how to read the nutritional labeling before choosing,” warns Sonia Martínez Andreu.
Raw fish analogues have been slower to join this select group of alternative proteins. Sergio Martínez, Director of Operations in Europe at Current Foods, has just presented his proposals for tuna and vegetable salmon for poke and sushi. He attributes the delay in reaching the shelves to the fact that it was easier for the market to start with alternatives of cooked chicken. “With raw vegetable fish, you had to mimic that shiny, juicy, fresh-looking texture. This operation requires other types of protein sources, a lot more research and a lot of taste tests to make them feel like real fish in the mouth.” His veggie fish contain pea protein, potato and bamboo fiber, salt and tomato lycopene to achieve a reddish look.
A vegan option from the sea
Others that reproduce at full speed are microalgae, microscopic unicellular beings made up of 70% protein of high biological value, polyunsaturated fatty acids and antioxidants such as astaxanthin and beta-carotene. Fidel Delgado, director of the Spanish company Neaoalgae, explains that they are isolating “proteins without color or aroma that could be added as one more ingredient in final protein foods, such as meatballs or vegetable burgers. They can even be blended as a supplemental protein in animal-based formulas to improve their nutritional profile.”
In second place, petri dish meatballs
If all of the above seemed weird to you, get ready to find out what your kids’ burgers will be like: 100% animal meat, but without the need to sacrifice them or feed them on millions of hectares of pastures. That is possible by culturing meat from stem cells extracted from live animals by biopsy. The process involves no genetic manipulation, no antibiotics – after all, they grow in an aseptic environment – and no suffering. These cells multiply in a controlled manner in a synthetic medium that reproduces the conditions of an animal’s body, like in The Matrix, but to form meat, chicken or fish.
It sounds like NASA stuff, but one of the four companies leading research in cultured meat is BioTech Foods: this Spanish company has just received a €753,000 ($809,000) grant from ICEX to scale up production. They hope to one day have the capacity to sell hamburgers or sausages in your local supermarket. “The results of this research project will contribute to developing the first industrial production plant for cultivated meat in Spain, one of the first in the world,” says the company’s co-founder, Íñigo Charola. The goal is to produce up to 4,000 tons of cultured meat a year.
Will there be lab ribeyes? It is possible. NovaMeat has already developed technology to produce complex pieces of cultured meat with 3D printers, with the texture of a real steak. “The holy grail of cultured meat is developing steaks or a fibrous piece of pork,” says Giuseppe Scionti, the company’s founder.
The sector is at its peak, and there are already companies cultivating oyster meat without the shell, prawns, Wagyu beef and even antelope. The handicap, however, is the energy cost. The cow gestates the calf without plugging it into the grid, but cultivated meat needs electricity 24 hours a day. For the independent environmental consultancy CE Delft, the solution is for industrial farming plants to switch to renewables. “Cultured meat has a similar average footprint to producing pork or chicken on conventional energy today. With sustainable energy, it will be much less than the rest of the conventional meats,” they explain. Even so, they recognize that tofu or legumes have a much lower environmental impact.
Next STOP: tailor-made proteins
Manufacturing custom proteins brings us a little closer to the dream of having truly functional foods, that is, with benefits for certain illnesses. This is the objective of Protección, a project led by Laboratorios Ordesa with the support of the Center for Industrial Technological Development of Spain (CDTI), which seeks alternatives to animal proteins from vegetables, fungi and insects. “We will study how these new functionalized proteins have an effect on the immune system and the metabolic processes associated with its modulation,” explains Dr. José Antonio Moreno, researcher at Laboratorios Ordesa and coordinator of the project. “The aim is not only to find alternatives to the more traditional sources of protein, but also to obtain extra benefits from the entire process.” It is difficult to discern which is the best protein, the one that feeds the most and has the least impact on the environment and on our pockets. What is clear is that we have many options to choose from, and we will soon have many more.
From biblical plague to sustainable food
A recent report from EIT Food recognizes that insects are the protein option that raises the most reluctance among consumers. In their favor, they reproduce easily, can be grown in a small space and provide a sustainable protein. At the moment, only three are approved to be sold in Europe: the migratory locust, the house cricket and the mealworm. The Austrian company Zirp Insects sells chocolates, snacks and burgers made with worms. On the other hand, not all insects reach the 40% percentage of essential amino acids established by the FAO, so it would still be essential to integrate them into a varied diet.
Sign up for our weekly newsletter to get more English-language news coverage from EL PAÍS USA Edition