A dietary instinct in humans ?

It is generally said that humans have lost their dietary instincts. It is clear that indulging your own desires in front of a full buffet, or in front of the family table, can lead to serious imbalances. Every moment temptations arise which push us to eat what we know to be harmful to our health, to reject the foods that are declared to us to be the healthiest, to destroy our teeth by dint of sweets or our liver by dint of alcohol. … If we let ourselves go, it is the specters of obesity, cardiovascular disease, cancer that threaten us and bring us back to order when all is well.

There is certainly nothing instinctive in the corrections of food hygiene that diet teaches us, it is on the contrary the mind, the reasoning, the control of appetites, even the calculations of food components that are supposed to ensure our nutritional balance.

The animal in the wild obviously has fewer problems. All the specimens of a species that you would pass on the scale will respect the same height-weight balance, there will be neither too thin nor too big, unlike what would happen if you passed on the same scale. different specimens of the human species. About four times as many irregularities (standard deviation the statistician would say). The difference is noticeable.

Can it be explained by better genetics? Wild animals are exposed to all kinds of dangers, and only the best performing animals survive and reproduce. We can therefore think that the genome of species that live in nature, without the facilities of civilization such as protection against predators, automated food supply, survival and reproduction guaranteed by medicine, must be more efficient than ours after a few millennia of “progress” of all kinds. Civilization lowers the selection pressure, and promotes the degeneration of the species …

This fine explanation collapses, however, when one domesticates a wild species and imposes a diet more or less similar to human food. Overweight appears in a few weeks or months. Conversely, if we feed specimens of our human species in the same way as the wild animal in nature, that is to say on the instinctual mode, the overweight quickly lose their unnecessary pounds, and the overweight lean gain in musculature (as long as the method is applied correctly). The average BMI (body mass index) is around 20 kg / m² on average for long-standing instincts and body composition (the ratio of the weight of fatty tissue to that of vital tissue) is significantly better.

As instincts in principle disregard any limitation or dietary recommendation, it is necessary to admit the existence of self-regulation ensuring appropriate caloric intake. Now, who says self-regulation, whether it is an animal or a human being, says ipso facto “instinct”, at least when it is defined as a set of automatisms aimed at ensuring the vital balance. of the body.

At the same time, it appears that this self-regulation does not work correctly in the culinary context. Experience shows, for example, that a domestic animal to which its master gives its own food without limitation of rations fattens abnormally, while the same animal receiving raw food, also without limitation, reestablishes normal weight within a few weeks. Same observation with the owner: if he goes instinctively, his overweight quickly begins to subside, and if he resumes the cooked diet, he puts back his extra pounds.

What logical conclusion can be drawn from these few observations?

  1. That there is a dietary instinct that spontaneously guarantees height-weight regulation, both in humans and in animals
  2. That this instinct is defective by the culinary preparation
  3. That it is genetically adapted to primitive foods and that the other functions of nutrition could also be.\

This is only half-surprising: the art of cooking is about making food better than raw; if there is a regulation of food intake based on the perception of flavors, improved flavors spontaneously lead to eating more. The role of flavors is obvious, a repellent flavor pushing to reject a food, and an attractive flavor pushing to consume it. It is therefore in essence that the culinary art defeats the mechanisms of taste regulation.

This small demonstration has been reinforced since the 1970s by the definition of food alliesthesia. The smells and flavors change depending on the condition of the body. More recent work has shown that the alliesthesic shift from pleasant to unpleasant is more blurred when a food is prepared. It is logical to think that the regulation provided by the taste sense is disturbed in the sense of overfeeding by the culinary preparation.

Taste alliesthesia is not, however, the only one to regulate food intake: feelings of fullness, independent of the volume occupied by the food in the stomach, also play a major role. Fullness is less disturbed by prepared foods, but observation shows that it is not as reliable. Refraining from any culinary preparation therefore seems essential for the rehabilitation of alliesthesia guidance, the centerpiece of the dietary instinct.

The question then arises to know to what extent this instinct is able to guarantee an adequate nutritional regulation, not only from the point of view of caloric intake, but of the balance between the various nutrients: carbohydrates, lipids, proteins, vitamins, minerals. and trace elements?

Daily experience shows that appetites, especially olfactory and taste attractions for foods rich in protein increase after a period of abstention. A lack of protein results in a strengthening of the attractions, and also in a feeling of proprioceptive satisfaction (mouth, esophagus, stomach) at the time of consumption. The same goes for foods high in lipids, or high in sugar.

These variations, which can be observed regularly, do not in themselves guarantee ideal self-regulation. They could only partially correct the previous overloads or deficiencies, or intervene only in cases of extreme deficiency. The question arises in an even more acute and complex way for the contributions of vitamins, minerals and trace elements. A double empirical answer is given:

The results seem conclusive, insofar as the practitioners

It may seem contradictory to say that the functioning of instinct requires the application of rules drawn from experience. Automatisms should occur spontaneously without being imposed on them. The answer is that these rules do not constitute limitations, but define conditions under which instinctive automatisms can manifest and be deciphered correctly.

Under natural conditions (absence of culinary denaturation), the child would go through a period of learning where he could do a whole series of experiences, each correct reaction to the indications of the senses bringing well-being and each error resulting in a discomfort (easily compensated by breast milk). This conditioning would constitute from the first stages of weaning an early learning, soon covered by infantile amnesia, but remaining active in the unconscious in the form of reflexes, awareness of certain perceptions, forecasting of the effects of each error.

The child who goes through this period of learning with denatured foods cannot register the relationships between alliesthesia variations (insignificant because of the denaturation) and consequences on the state of the body. He will suffer from “alliesthesia blindness”, that is, an inability to read perceptual variations the usefulness or harmfulness of the food consumed. He will simply not pay attention to the indications of the senses, confusing for example quantity of pleasure and quality of pleasure, he will seek satisfaction in the sophistication of the preparations instead of seeking it in the adequacy of the food to his real needs, he will not develop the natural sensitivity of the senses of smell and taste. This is why a whole series of rules, constituting a real learning a posteriori, proved to be essential.

To sum up, we can say this: the dietary instinct still exists in humans, it is like any genetically determined instinct, but it can only be expressed correctly in a food context sufficiently close to the primitive conditions which presided over the development of the genome. In addition, like any instinct, it requires a part of learning; as this is not carried out in the early period, or being misled by culinary denaturations, relearning is essential a posteriori in order to at least partially recover the instinctive self-regulation of nutritional balance.

And perhaps the main thing: instinct is expressed through pleasure…