How does an organism exist and develop? We commonly speak of the number of calories in different types of food products. The main idea seems to be that the more calories we consume, the more weight we gain. Simple Western dietary systems are based on the calculation and restriction of calories. However, after initial enthusiasm for this system and after thousands of pages published on the subject it was discovered that in most cases it simply did not work. An individual organism is much more complicated than an oven, where you can calculate heat produced from the fuel loaded. Some people can eat quite sparingly and stay active and healthy; some need a lot of food all the time. Many families suffer from the permanent hunger of growing children.