There is a metabolic adaptation during pregnancy. Hormonal changes stimulate adaptation in purpose to fulfill the needs of the fetus and the mother for nutrients. A great number of physiological changes occur in pregnancy depending on gestational age. Fetus growth depends on the mother's energy status before pregnancy and the quality of her life conditions during pregnancy. Speaking of quantity, a pregnant woman must not eat for two, the caloric value of her diet during pregnancy should contain only 200 to 300 kcal/day more compared to her diet not being pregnant. Healthy diet in pregnancy does not differ from healthy diet in any other life period. Rules are the same during pregnancy and not being pregnant, which is a rich and varied diet, a vitamin and minerlas-rich diet, low sugar and fat, a small amount of kitchen salt and whole grain products on a daily basis. During pregnancy there must be specially payed attention on following instructions: not to smoke, not to drink alchocol, drink adequately, not to eat insufficiently thermal treated meat (danger of toxoplasmosis), not to drink unboiled milk and diary products (danger of listeriosis). Diet and drink habits have a far stronger influence on our health than we had previously assumed, and diet gets special value and importance in pregnancy. Although there are no strict rules on weight gain, there are still suggestions that pregnant woman should reach 2 to 3 pounds by the 20th week and in addition half a pound every further week, which would end up to 12 to 14 pounds by the end of pregnancy (17).