WHY WE EAT WHAT WE EAT?

The composition of our diet partially reflects our body composition and from these it is possible to obtain some information about the quality of our feeding. However, the question may be, do we eat that we really need to eat? Or, why we eat what we eat? The human body is the result of the highly regulated expression of our genes, and our genetic heritage is the result of a constant evolutionary process of millions of years. Almost the totally of our genome was formed during the pre-agricultural era and we suppose that this is the optimal informational patrimony for the normal development of our life. This genetic patrimony has allowed our adaptation to the constant modifications of our environment, particularly to the climatic variations where our ancestors developed millions of years ago. Our genetic patrimony was slowly molded, without important changes, during each of the steps of the evolutionary process, from the Ardipithecus ramidus of arboreal life until the present Homo sapiens sapiens, determining our actual nutritional requirements. During these evolution steps aroused the "thrifty genotype" expressed as tissue leptin resistance and differential insulin resistance. At present the expression of the thrifty genotype is not necessary and the effects of its action are associated with the opulence diseases; obesity, cardiovascular diseases and diabetes, among others. This work discusses why we have reached to eat what we eat and how the evolution of our feeding can be related with diseases of high prevalence in the western world.