2008, Number 6
Bol Med Hosp Infant Mex 2008; 65 (6)
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ABSTRACTDiet has been a strong selective influence during human evolution, and it has contributed to the consolidation of the human genome. This process can be traced back to 4.0-4.5 million years ago, when the first hominids derived energy and proteins from fruits, vegetables, and roots. The transition from arboreal existence to life in the plains was possible through the emergence of traits such as the erect posture, naked skin with numerous sweat glands, and dark skin color. This new adaptation significantly expanded the area of influence of hominids and made possible the emergence of new dietary practices like scavenging, hunting and anthropophagy. In the next evolutionary line, Cro-Magnon and other modern humans improved hunting strategies with an increase to nearly 50% the proportion of meat in the diet. In the Paleolithic period (~ 60 000 yr), overexploitation of resources, climatic change and population expansion made human ancestors less dependent on large mammals and led them to a more diverse diet which included fish, seafood, and small animals, plus vegetables processed with new technologies, i.e grinding stones, and mortars. Macronutrient composition of the Paleolithic diet was 37% protein, 41% carbohydrates and 22% fat, with a favorable polyunsaturated/saturated fat ratio and low cholesterol. The emergence of agriculture and animal husbandry, and more recently of the industrial revolution, has modified the diet without parallel changes in the genetic structure, a condition named evolutionary discordance. The agriculturalists depended up to 90% of their energy requirements on cereals, a pattern which explains the high prevalence of protein energy malnutrition, and other deficiency diseases in these populations. In more recent times, the industrial revolution induced lower energy expenditure, higher intake of saturated fats, omega-6 and trans fatty acids, with less consumption of omega-3 fatty acids, complex carbohydrates and fiber. The food groups with major changes were cereals, dairy products, refined sugars, refined vegetable oils, and meat from animals reared in confinement. The health risks associated with these dietary changes are at the root of the present epidemic of nutritional-related chronic diseases. It would be advisable to look back to the Paleolithic diet, and to consume more vegetables and fruits. We have the advantage that present day food technology offers many possibilities to have access to a low-cost diverse diet.