 are inferior to many other products of plant and animal origin.
So, on average, an adult needs to receive from 2500 to 4000 kcal per day with food, depending on energy costs, which are determined in turn by the degree of activity of his lifestyle and the nature of work. The calorific value of 1 kg of fresh green peas, sweet corn and potatoes is only 750-940 kcal; watermelon, melon, cabbage, onion, root vegetables (except radish) - 300-500 kcal; cucumber, tomato, pepper, eggplant, spinach, lettuce and pumpkin - 150-270 kcal; thermal energy 1 kg beef and of bread is 2000 kcal, and fat - 8800 kcal. On average, it is believed that a kilogram of vegetables contains 837-209 kJ, while the energy potential of a similar amount of meat and fat is 8400 and 36 960 kJ, respectively.
However, in the collection of kilocalories from a unit area, vegetable crops are not inferior to cereals. For example, wheat gives an average of 1 sq. m 870, and a tomato 1254 kcal. But it turned out that this is not the most important thing, since in the final analysis it is not so much the yield in terms of caloric content that is important, as the yield of vitamins from 1 m2 of vegetable crops.
Vitamins are a group of biologically active organic compounds contained in very small doses and necessary for the normal functioning of the body. Unlike basic nutrients (proteins, fats, carbohydrates, mineral salts), vitamins are not energy sources and plastic materials. They are necessary as essential components of metabolism. Vegetables are the main source of vitamins.In the human body, vitamins are catalysts for biochemical reactions and regulators of basic physiological processes, metabolism, growth, reproduction. Due to vitamins, vegetables also contribute to a more rational use of protein in the process of human nutrition.
In this regard, in recent years in many countries of the world, vegetables have become increasingly important. Particular attention is paid to the production and consumption of a whole group of vegetables, united under the general conditional name green-yellow (or yellow-green) vegetables, which it received from the characteristic color of the productive organs (leaves, fruits, root crops, etc.). For what reason has this group of vegetable plants attracted close attention, and not only vegetable growers, but also doctors? For example, in Japan, the consumption of green-yellow vegetables is controlled not only by the Ministry of Agriculture, but also by the Ministry of Health. This is primarily due to the fact that in the highly developed countries of the world these vegetables are becoming increasingly important in connection with a new approach to the problem of public health, the main goal of which is not treatment, but prevention of diseases, and increasing the resistance of the human body's immune system.
Therefore, numerous scientific studies were carried out, the results of which clearly proved the outstanding role of the green-yellow group in the prevention of various diseases, and with a much higher level of effectiveness than expected, and which can be achieved using medicines synthesized by the chemical industry, and even then when the latter are powerless.
What is the reason for the effect of green-yellow vegetables on the immune system of the human body? First of all, with a high content of "raw" or "fresh" provitamin A - beta-carotene. As it turned out, the functions of vitamin A are much broader than it was originally assumed and about which are known to wide circles of the population: a beneficial effect on the growth processes of the body, human vision, the physical condition of the skin, hair, etc.
A whole series of research works have shown that vitamin A deficiency leads to reduced resistance against infectious diseases. In connection with A-avitaminosis, many doctors also put the formation of stones in the urinary and gall bladders, catarrh and infections of the digestive tract, lungs and a number of diseases. It just so happened, unfortunately, and this is one of the troubles of mankind, that the characteristic prop