The quality of food is determined by two major factors: energy intensity and complexity of the necessary ingredients (proteins, fats, vitamins, minerals).
Saturation energy (or calories) of food is determined by the energy stored in food: proteins, fats, carbohydrates. This energy released by the oxidation of food in the human body and used when produced by the body work, usually measured in calories (cal) or kilocalories (kcal). According to experts of the Food and Agriculture Organization (FAO) and the World Health Organization of the United Nations (WHO), the average human diet must contain at least 2,500 calories. (Of course, much depends on age, physical activity, the natural conditions of the area and so on. D. Thus, for a normal adult human daily nutrition required for 1 kg of body weight of about 43 kcal, pregnant women and nursing mothers - 50 calories, while a growing child up to 10 years - 100 calories.) However, according to available data, 2500 calories per day (or about as much) is only 35% of the world's population; another 15% of the inhabitants of the planet, consuming the appropriate dose of calories are deficient of certain nutrients, especially protein of animal origin. Finally, a fifth of the world's population is undernourished absolutely, getting less than 1500 calories daily.
The second indicator of the quality of food - an assortment of consumed nutrients. At one time it was thought that the different kinds of food are interchangeable and only have to give the right amount of calories. This mechanistic theory called izodinamii (from the Greek. Ise - equal, dinamic - force). However, only carbohydrates and fats may be partially interchangeable, proteins, especially of animal origin, can not be replaced by anything. The same can be said of certain vitamins, although their role and power is negligible.
Quality of food: facts and rules