Alimentatia corecta - partea I tradurecea in romana a materialului   "Nutrition"      Nutrition is essential for health. The diet must be adequate in quantity and quality, must be regularly, correct fractionated and complete, covering all the energetic and plastic necessities. Nutrition must contain following categories: saccharides (carbohydrates), fats, proteins, vitamins, minerals, water. In addition, vegetal fibers are needed.      Aliments need for digestion and absorption energy consumption. This is called SDA (specific dynamic activity) and is in average 6% for saccharides, 12% for fats and 30% for proteins! But there is a great variation! There are aliments with negative ADS (eating them brings no energy, it even consumes energy!!!) Energetic efficiency is also very different.      The "energetic needs" include the needs for:   1. The "basal metabolism" (for functioning of the circulation and respiration, for maintaining the tonus of the muscles and for the surviving necessities of all cells...);   2. Muscle activity   3. Thermoregulation (maintaining the normal temperature of the organism);   4 The SDA (specific dynamic activity) of the aliments = the energetic consumption for the digestion and absorption of food. The energetic needs are covered by saccharides, fats and proteins.      The "plastic needs" include the need for regenerating the structures of the organism. All cells, excepting the nervous ones, are periodically replaced! These "plastic" needs are covered by proteins, water, minerals and vitamins and also some fats and saccharides.      The needs are deeply influenced by a lot of factors: age, sex, mass, weight, muscular, nervous and endocrine activity, stress, temperature and humidity of the environment, clothes, health, medication...      Our organism (especially the liver) is a fantastic biochemical plant. It can produce most of the necessary substances and convert a category in another (fats into saccharides, saccharides into proteins a.s.o., depending on the available nutrients and the necessities). But not anything! There are nutrients which are vital for the organism but cannot be produced by ourselves: The so-called "essential amino acids" (components of proteins), "essential fat acids", minerals, water, some vitamins....      The digestion and absorption of the aliments is influenced by a lot of factors: How cooked they are and how fragmented (chewed) they are; what other nutritive elements or chemical substances there are in the same aliment or the others eaten at the same meal; the physical, nervous and endocrine activity in the period of the digestion; the function of the stomach, lever, pancreas a.s.o.; the passing speed, the pH, the bacteria and presence of other chemical substances in the intestine and other factors. Therefore, there is no direct and proportional relation between the composition of the ingested aliments and what your body has absorbed in reality from what you ate! Absorption efficiency varies from 100% to 0 % !!!!      There is no absolute concordance between the appetite (hunger sensation) and the real necessities! In many cases, our natural regularization works inaccurate (highly purified or very cooked / artificially modified aliments, presence of additives, condiments, special environmental circumstances, activity and health estate of different systems of the body....)      The organism has reserves for most categories of nutritive substances. These reserves are formed when the ingestion (or own production) exceeds the needs and are consumed when the needs are higher than the ingestion (or production in the organism). Therefore, the stocks are consumed in the case of reduced or absent ingestion or an increased consumption (stress, illness, effort...) of that substance or other substances which the organism must produce itself and can synthesize on the basis of that stocked substance. Some reserves are enough for many years and the absence from your diet for some weeks or months has no bad influence on your health unless the needs do not rise suddenly because of a special situation. Other reserves are very small or absent ant the absence of that element from one's nutrition produces rapidly negative effects.      There is no direct relation between the negative health effects of a deficiency of a class of aliments or a substance and the percent or quantity that is necessary under normal circumstances. Some minerals are needed in extremely small quantities but their deficiency has severe or even fatal effects.      Never skip breakfast! No excess! Eat at the same hours! Fractionate your diet in 4-5 meals / day!      Energetic value of the diet depends on many factors (see above). In average, an adult needs in normal circumstances (without cold or significant physical effort!) around 3500 kcal / day.