With general character, which is fattened or become thin is the difference, positive or negative, respectively, between the ingested calories and the spent ones. Vista thus, the fat that we accumulated is not more than an energy reserve. But the personal differences cause that the question is not so simple. First of these differences one talks about the basal metabolism, that is the minimum amount of energy that a person needs to live: to breathe, to maintain the activity, the operation of the kidneys, the brain, etc. cardiac Are, in summary, the power consumption in absolute rest, and vary from a person to another one based on a series of factors like age, sex, height, weight, stress and others. Relatively small differences in the basal metabolism of two individuals can be in the end important, since esteem that this metabolism supposes around the 55 70% of total the power consumption, corresponding the rest (30 45%) to the physical exercise and the heat production.
The other factor that differentiates to people from others is the saving genotype, that is to say, the genetic predisposition to save energy and to accumulate it in the form of fat. After ingesting food, which supposes the glucose presence in the blood, there are organisms that feed in abundance certain cells on the body, like the muscular ones, and so it is not hardly energy to be stored in the form of fat; on the contrary, others have developed ” habilidad” to feed these cells with frugalidad and to store the leftover energy like greasy matter. The saving genotype has been, during thousands of years, a clear evolutionary advantage. Before the frequent periods of prolonged food deficiency for want of hunting or harvesting, the individuals with saving genotype had more reserves (greasy) to survive, whereas those that did not have this genotype could die of hunger. But our developed society, of abundance of tempting and cheap food, this advantage has become, as we know, in disadvantage. Besides these two factors, it could not yet have others shortages that mark more differences between people and others. Anyway, the knowledge of these circumstances would have to tranquilize you bring back to consciousness and to extinguish culpabilities, but never to relax efforts nor to induce to the fatalism of those who undergoes overweight: to become thin, besides very advisable for them, is possible.