Online there are many pseudo-scientific websites trying to prove that humans are not omnivores. According to their bizarre theories, meat would not be suitable for humans: let’s see what are the most common and fanciful motivations.

• Humans are unable of tearing to pieces a pray still alive and tearing raw meat with his teeth

According to this explanation, meat is not a suitable food for us, because we do not eat it as predatory animals do in nature, but we can consume it only after various processes such as maturing and cooking. The comparison of human and animal behaviour does not make sense. Human has evolved and thanks to his intelligence has developed techniques to make food more suitable to his needs.

It is true that meat needs to be processed to make it softer, digestible and appetizing, and to increase its safety from a health point of view, but this is not a valid motivation to consider it a food not suitable for our body.

According to this point of view, even foods such as soybeans, cereals and some veggies would not be suitable for human consumption, as these must be transformed to be edible. An example are legumes, which need to be soaked and cooked to deactivate otherwise toxic substances for humans. Or for instance soybeans, that we cannot consume as they are, but only after treatments such as fermentation and sprouting, in order to obtain some benefit.

Which animals in nature are able to do that?

• Our teeth are similar to herbivores

Indeed, our complete and multifunctional teeth are very different from herbivores and have many characteristics confirming that humans are omnivores: we have no endless growth teeth, we are unable to grasp and to cut grass with incisors and to browse like herbivores; we have no molars suitable for breaking plants into small pieces and we cannot easily swallow too fibrous and coarse foods.

In addition, the area between the canine and the first premolar is very sharp, similar to carnivores’ teeth and is suitable to cut off a piece of meat. Even our molars are much more similar to those of carnivores and omnivores than those of herbivorous animals.

• Humans are frugivores, as they belong to primates, which are frugivores

Indeed, not all primates are frugivores, most of them are omnivores, including Chimpanzees and Bonobo, the species closest to Homo sapiens. These are used to eat flesh, actively hunting other animals in the forest, plundering eggs and little birds born from birds’ nests, as well as routinely eating insects, using sprigs to extract ants and termites. Animal proteins are therefore strongly represented. Furthermore, among chimpanzees the cannibalism and the killing of puppies is common.

Often, those interested in promoting a strictly vegetarian diet take as an example the nutrition of another of our “relatives”, the gorilla, claiming that since it is herbivore and it eats only some insects as the only animal protein source, which is less than 1% of its total food intake, then also humans should eat this way.

Comparison with gorilla does not make sense: not only because we have evolved and now we are a completely different species from gorilla, but also considering that gorilla can eat 30 kg of vegetables a day, to eat like it humans should ingest 14 kg of raw vegetables a day, which is not very good for our stomach and intestine. And then, who can do it?

• We do not have the required enzymes for digesting meat

This is another huge falsity. In fact, we have lipases, enzymes which degrade fats, such as triglycerides, which are only from animal origin and not from vegetables. Moreover, we have pepsin, an enzyme that attacks proteins to break them down into amino acids. So, nature has genetically programmed us for perfectly digesting meat, existing in our diet for hundreds of thousands of years.

• Our intestines are too long and meat putrefies in the gut

Our small intestine is 8 to 9 meters long: here the food is demolished and reduced to simpler substances to be absorbed. Then it passes through the large intestine, which is 2 meters long, where food ferments and decay, forming the very important bacterial intestinal microflora. In this section not only meat, but also fruits and vegetables decay, and it is a completely natural process necessary for the formation of symbiotic bacteria.

Human’s intestinal length is the same as omnivorous animals, and the statement claiming that carnivores have short intestines to allow meat to remain there as short time as possible is unfounded. In fact, the mammal with the longest intestine is sea lion, which is carnivorous, while salpa fish is the animal with the longest intestine and it is omnivorous. Intestinal length is therefore not a good criterion for the distinction between carnivores, herbivores and omnivores.

Other characteristics in favour of the omnivorous diet for humans are the presence of opposing thumb, suitable for grasping prey and building weapons, to cope with the lack of claws. Also, eyes to the front of the head is a characteristic of predators because it allows binocular vision; on the contrary preys have their eyes sideways to broaden the visual field as much as possible, to be able to see and escape from predators.

However, trying to build a unique omnivorous mammalian scheme is extremely simplistic: just think about the differences that exist between bear and pork, both omnivores, but with a very different diet.

Comparing humans to herbivores does not make sense, as it does not make sense to compare them to carnivorous predators: a diet composed only by meat would be deleterious, as would be a diet made of just vegetables. Meat intake is perfectly functional to our digestive abilities and must be present in a complete and balanced diet, which involves intake of both plant and animal foods, without any exclusion.

Susanna Bramante

Susanna Bramante is an agronomist, nutritional consultant and scientific writer, author and co-author of 11 scientific publications and numerous articles on human nutrition and its impact on health and environment. In 2010 she received the title of Doctor Europaeus and PhD in Animal Production, Health and Food Hygiene in countries with a Mediterranean climate.