Translated from the Latin word "diet" refers to the daily portion of food, and the word "rational" respectively translated as reasonable or appropriate.
Meals can be rational only if it meets the demand of the human body in a plastic (construction) materials, fills it with no excess energy consumption corresponds to the physiological and biochemical capabilities of a person, and includes all other necessary materials for it: vitamins, macro-, micro- - and ultramicroelements free organic acids, ballast substances and other biopolymers.
Since all of the above comes to us from the outside, a balanced diet can and should be regarded more as a naturally due to the relationship of man with the habitat. But of all the agents of the environment food differs in that the inside of our body, it becomes an internal, specific factors for him. Some elements that make up this factor, converted into energy of physiological functions, others - in the structural formation of organs and tissues.
Nutrition of any person must be rational, ie, a reasonable and scientifically sound, feasible. This is the ideal, which achieve in real life is not easy, and to be entirely honest, it's impossible, but it should work. The term balanced diet should be understood physiologically balanced diet, taking into account the specifics of each person is able to ensure consistency of its internal environment.
And yet, what are the fundamental laws of nutrition?
The dominant position of the theory of a balanced diet - it may be said, the practical realization of the postulates of the theory of adequate nutrition.
The first law, nutrition talks about the need to maintain a balance between incoming energy from food, ie, the caloric content of food and energy costs of an organism. Caloric content of food - a measure of energy value, equal to the amount of energy (calories) are exempted in the oxidation of nutrients that make up the food. To measure the calories (energy value) and the work of the body (energy costs), use the same units - in calories (cal) and kilocalories (kcal), and in the international system of units - joule (J). One calorie is equal to the cost of heat to heat 1 gram of water 1 ° C. To convert to joules need 1 cal multiplied by 4.184. One kilocalorie equals 1000 calories.
Even under conditions of rest and under favorable temperature conditions, the level of energy costs an adult is 1300-1900 calories per day. This so-called primary energy metabolism, which can be calculated for each person in the following way. It was established experimentally that the specific exchange of energy in 1 hour is approximately 1 kcal per 1 kg of body weight. Hence, the main exchange in a man weighing 70 kg is equal to 1,680 kilocalories (1 kcal x 70 kg x 24 h).
Any physical or mental work requires additional energy costs. If the people involved sedentary sedentary "work, the daily energy requirement of 2500-2800 kcal, for persons engaged in heavy physical work, these values may reach 4000-5000 kcal (see Table 1.).
Table 1: Energy consumption for various types of work Name of the energy costs per hour per person with 70 kg, kcal
Running at a speed of 8 km / h
The main energy material human body give carbohydrates and fats as well as proteins are mainly used as a plastic - a building material. However, their abundance also may be spent for energy. Thus, the energetic material used in the body only needs, and if the daily caloric content of food energy consumption exceeds the body, the uncalled portion of fat is deposited in a special depot. Likewise, the "unburned" portion of carbohydrates is converted into fat, increasing overweight. Any deviation in the energy balance is not indifferent to the organism. For example, if daily calorie food exceeds daily energy consumption of only 100 kcal, the annual excess fat a person to grow by 1,75-3,5 kg and 100 kcal from the body receives 50 grams of white bread or a teaspoon of sugar.
When restricted diet, ie, short-term lack of energy material in the human body are spent his spare substance - glycogen and fat. Under conditions of prolonged lack of food (starvation) to cover energy costs are not only fat and carbohydrates, but also proteins of the organism. Therefore, to maintain energy balance so necessary for the optimal number of nutrients.
Part of the energy the body expends directly to the digestion of food, while the number of energy used depends on the composition of the diet. So, on the digestion of protein organism spends 30-40% of the energy in the digestion of fats - 7-14%, Carbohydrates - 4.7%, raw vegetables - up to 60%. Why does an incredible amount of energy is spent on vegetables? They are very poorly lit, as they have a lot of water. This is another valuable raw vegetables with them the body gets plenty of useful nutrients, but more than half the energy of the material received is spent on their own digestion. Eating raw vegetables every day, even pounds, it is impossible to suffer from obesity.
Another thing carbohydrates or fats, which are very easy, without much energy, absorbed by the body. Therefore, all the received energy must be spent not on their learning, and to perform physical work, otherwise the carbohydrates turn into fat. When burned in the body of 1 g of protein and carbohydrate is allocated 4.0 kcal (16.7 kJ) energy, whereas the combustion of 1 gram of fat - 9.0 kcal (37.6 kJ).
Now once again refine the basic meaning of the concepts already mentioned several times - the biological and nutritional value of food.
Biological value of food primarily determines the characteristics of its own participation in the synthesis of proteins of an organism, and also takes into account the activity of its constituent fatty acids and vitamins.
Nutritional value of foods - a concept more widely. This takes into account and the energy value of the product, and it contains organic biopolymers, and inorganic substances, and even the taste of food. The most common nutritional value accounting - is grams or milligrams of nutrient per 100 g edible portion of the product. Nutrients known substances contained in foods and used by the body.
Therefore, it should be noted that 100 gmyasaeto than 100 grams of protein, as well as 100 grams of bread is not 100 grams of carbohydrates. For this there are conversion factors of food in clean substrates. In view of these factors compiled in Table. 2.
Thus, a balanced daily diet of an adult should include an average of 1900 ml of fluid (in the drink, in a dish and a "dry" products), 90 grams protein, 90 g fat, 450 g carbohydrate, 0.1 g of vitamins, 20 g of mineral substances, trace elements and ultramicroelements. Total to meet the needs of the human body should be more than 600 different substances, including the 8 essential and 10 nonessential amino acids.
At large, and even more so when excessive physical or mental stress the need for certain nutrients increases, the other decreases. Changing needs of the body and for some diseases.
Energy costs teenagers about 1700 calories more than children aged 1 to 3 years. A daily diet of people aged 28 to 39 years, ceteris paribus, on average contain 200 calories more than a diet of 40-60-year-old men.
In women, energy costs are generally lower than in men, and if she eats on a par with men, it inevitably begins to gain weight.
Thus, considering the first principle of a balanced diet, we can conclude that food is necessary to observe moderation.
This condition is the key to escort the physical health and outer beauty.
Table 2: Energy value of some foods (kcal per 100 g edible portion of the product)
The second law of nutrition is that it is necessary to adhere to a balance between coming into the body proteins, carbohydrates and fats with vitamins, minerals and ballast components.
Under this law, to lead a full life and stay healthy person does not need any specific product, and in particular - the optimal - the ratio contained in these nutrients. For the normal development of the human body should be a systematic flow into it about 70 food components, which itself does not synthesize the human body, and receives only with food. Such a number of valuable dietary components can not be in any one, even the most valuable product. Their partially contain different food products: meat, fish, cereals, vegetables, fruit, berries, etc.
For various population groups, there are specially designed rules physiological needs for nutrients and energy, which are based on scientific evidence, physiology, biochemistry, nutrition and other branches of medical science, role, relationships, absorption of some nutrients and the norms of their true needs.
To determine an adequate amount of energy for specific groups of people, it is necessary, in accordance with the recommendations of the World Health Organization, to correlate overall energy consumption for all types of human activity with the value of its basic metabolism, ie, the energy consumption at rest. Ratio of total energy consumption to the value of basal metabolic rate gives a physical activity. For example, if the age and sex for a certain group of people the energy consumption for all activities in the 3 times larger than the basal metabolic rate, which means that their rate of physical activity is 3.
Workers employed light work, with little physical activity, have a coefficient of this activity 1,6. In this group, according to the recommendations include drivers of trams and trolley buses, workers conveyors, packer, seamstresses, vesovschits, radio-electronic industry workers, nurses, agronomists and Communication Workers, service, sales of manufactured goods, etc.
Given that energy demand in this group amounts to 2500-2800 calories a day, they need to eat daily meals containing 72-80 g protein, 83-93 grams of fat and 366-411 grams of carbohydrates. Oscillation digits depends on age and sex worker. According to the recommendations of the Institute of Nutrition, proteins in the human diet should be 12-14% and 60% of this amount should be animal protein. Proportion of fat is 30%, including at least one third should fall on vegetable fats. For carbohydrates is 56-58% of total calories daily diet.
The most common forms of eating imbalances usually associated with inadequate intake of essential amino acids, fatty acids, vitamins A, E, C and B group, dietary fiber (dietary fibers), some mineral salts and trace elements.
Thus, the second law of nutrition can be summarized as follows: in order to be healthy and beautiful, you need to eat varied food.
The third law requires nutrition from a person a certain diet, ie, the distribution of meals during the day, enabling compliance with food temperature, etc.
Adult life is characterized by a dynamic equilibrium between the intake of nutrients, the process of transformation and excretion from the body in the form of the decay products. For every substance that enters the body with food, there are strictly defined laws of its transformation, its pathways. Therefore, both should be regularly and optimal distribution of food during the day.
The fourth and last, the law requires a balanced diet to take into account the age and needs of the body in accordance with them to carry out the necessary preventive adjustment of the diet.
Long-term age-related imbalance between intake of any substance into the body, on the one hand, and its decay or excretion, on the other hand, leads to an asymmetry of metabolism. It's safe to say that the age metabolism is closely associated with the occurrence of such widespread diseases as excessive obesity, atherosclerosis, the accumulation of salts, etc.
Because it is so necessary to the daily diet to ensure timely and complete satisfaction of physiological needs of the body for essential nutrients.
Implementation of the laws of nutrition guarantees the preservation for many years to high physical and mental activity, vivacity and cheerfulness.