September 26, 2020

how humans survived during its first two million years


“Tell me what you eat and I’ll tell you who you are”. When the French jurist Jean Anthelme Brillat-Savarin published this phrase in what is considered the first treatise on gastronomy, he surely did not think of the dietary tribes of today, ranging from those who reject the consumption of food of animal origin to who cry out for a return to feeding their ancestors. However, although changes in diet have been a constant throughout history, the reality is that for most of human existence, these changes were not a choice, but the only path to survival. Although it was in the days of Brillat-Savarin, after the French revolution, when gastronomy became popular and spread throughout Europe, the great changes in diet that marked the evolution of humanity as a species began millions of years earlier, at a time in which neither agriculture nor livestock farming had yet developed.

These changes, explains Ana Belén Marín, head of the group of human evolution and ecological adaptations of the Institute of Prehistory of the University of Cantabria, to eldiario.es, “are what allowed us to survive as a species, since if we do not eat there is no adaptation , neither evolution, nor survival. ”

Before the arrival of the first humans, explains Marín, “the hominids that existed had a diet very similar to that of today’s chimpanzees, where the plant component prevailed”, basically fruits, leaves, insects and even some roots. This type of diet accompanied the human species for much of its evolution, however, a series of changes forced members of the genus Homo to introduce new foods and abandon the vegetarian diet to become omnivores.

“The first major evolutionary change in the human diet was the incorporation of meat and fat from large animals, which occurred about 2.5 million years ago,” explains Marín. “We would not have gotten to where we are as a species without the inclusion of meat, because it provides a series of calories, amino acids and other nutrients that plant resources cannot provide.”

Human machinery and its fuel

One of the first questions that arise is why the first humans were forced to eat meat, and to answer it, one must attend to “two important factors”, according to the head of the paleophysiology and human ecology group at the National Center for Research on Human Evolution, Ana Mateos. On the one hand, “the physiological evolution of humans, that is, changes in our machinery”, and, on the other, “the resources offered by the environment”.

From the point of view of the evolution of the body, “humans have been incorporating foods of animal origin, which are high in calories, because our brain and body needed it,” explains Mateos. “The body and brain of different Homo It has been growing and this, at a metabolic level, requires an important energy contribution, “concludes this researcher.

Furthermore, this increase facilitated the development of new skills by humans. “Eating meat did not make us smarter, but it did develop skills that helped us survive,” says Mateos, especially in an environment where significant environmental changes were taking place.

“In that period, in Africa there was an important climate change in which the savannas were established, with which there were no longer resources all year round and it was necessary to look for alternatives”, explains this researcher. Many of the plant species consumed by hominids adapted to this change, generating thorns or producing less succulent fruits and more difficult to chew and digest.

However, animals could provide a continuous and abundant source of calories throughout the year, but to achieve this it was necessary that new Homo they had certain improvisational capacities, which implied greater intelligence. Ultimately, the increase in brain size required humans to introduce meat into their diet and to obtain this food it was necessary to be more intelligent.

Improved hunting and the arrival of fire

But, despite starting to eat meat, we were still “not hunters”, Marín clarifies, since “the consumption of meat was occasional and through scavenging, that is, from prey killed by other animals, since we were only an agent secondary “, so the proportion of meat in the diet could not be very high. Several thousand more years had to pass before other species of the genus Homo They will refine their tools and hunting gear, which happened approximately 400,000 years ago.

However, as much or more important than the development of hunting, it was the next great leap in the history of human food: the discovery of fire. “Fire makes food easier to digest, less toxic, tastier … and this was a milestone,” says Mateos. From that moment, which occurred approximately half a million years ago, humans began to develop different ways of processing food, although it was not until the arrival of the Neanderthals, about 200,000 years ago, when, according to Mateos, it begins ” the true cuisine of humans. ”

“We have a lot of archaeological evidence indicating that Neanderthals had a very varied diet and that they developed quite optimal hunting techniques,” explains Marín, who runs a project funded by the European Research Council aimed at studying the extinction of Neanderthals. In addition, thanks to the development of increasingly precise techniques, some erroneous ideas that were held about this human species have been banished “such as that they were rude men who only ate meat,” says this researcher.

Finally, with the arrival of Homo sapiensNew methods of food processing also arrived, such as drying, freezing or smoking, and even the fermentation of some products. Furthermore, the new human populations also became habitual shellfish and the consumption of mollusks was an important source of protein and energy that further diversified human diets.

More meat or more vegetables?

However, despite numerous studies, the reality is that it is very difficult to know precisely the proportions of the different foods that made up human diets. “Most of the measures are indirect, through dental morphology, of the wear of the pieces, to know if they had a hard or soft diet, or through accumulated tartar,” explains Marín.

In this sense, it is particularly difficult to obtain data on foods of plant origin, since animal remains are more easily preserved, which caused many researchers to give more importance to meat and despise the consumption of other types of resources. In this sense, an article published in the Nutrion Bulletin early in this century, he concluded that “knowledge of the relative proportions of food of animal and plant origin in the diets of early humans is circumstantial, incomplete, and debatable.”

The new techniques, however, make it possible to analyze dental remains more precisely in order to know the type of diet followed by humans from the past and “if there are no remains, we can reconstruct the environment in which they lived and see what resources were around them “explains Mateos. “The insects or the larvae, for example, hardly fossilize, but we know that chimpanzees eat them often and that they suppose for them a habitual source of protein and fat, so it is normal that humans would also have taken advantage of this resource ”

In addition, to this we must add the geographical diversity that existed among the different groups of humans that had spread across the planet, for which Mateos assures that “it cannot be said that there is a particular paleodiet, but several, because each group human lived in a different geographical and ecological context, with different resources. ”

The modern Paleodiet

Despite this diversity and the complexity of determining the diet of the first humans now, in recent years what is known as Paleodiet has become popular, a diet that starts from the idea that humans only It has adapted to the foods it ate during the two million years that preceded the emergence of agriculture and livestock, approximately 10,000 years ago, so it rejects products such as cereals, dairy products or, more recently, processed products.

However, although this movement starts from some certain data, most of the researchers who have studied the human diet during the Paleolithic are critical for its oversimplification. “It makes no sense to compare the foods that emerged from the Neolithic revolution, such as cereals, dairy products, or domesticated animals, with the ultra-processed ones that have emerged in the last 50 or 60 years,” says Marín.

Among the most common assertions made by those who defend the paleodiet is that we are the only mammals that consume milk in adulthood, something that the first humans could not do. However, Marín states that “despite the fact that 10,000 years ago humans were not lactose tolerant, now we are adapted to consuming dairy products, just as our intestines adapted to consuming meat.” The reality, says this specialist, is that “genetically we have been evolving and adapting to the environment in which we have been living in each period.”

Mateos also agrees with Marín’s criticism, adding that “one cannot extract only a partial vision of the past to make a generalization of what would be desirable today” and recalls that “as sapiens, our genome already contains these changes and adaptations. “In addition, Mateos points out that” the evolution of gender Homo it is a process that has not finished “and warns that” removing certain nutrients from our diet will probably have an impact in the future. Evolution will say – concludes that researcher – who was right. “

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