Doctor Lotte Lauritzen from University of Copenhagen considers that it is necessary to recollect the forgotten custom to give to children cod-liver oil. According to the doctor, it will help to prevent the most serious problems of modern children – excess weight and a high pressure. Cod-liver oil reception should be begun at excess weight first signs, without expecting, when the problem will appear too difficult. As have shown experiments, inclusion in a cod-liver oil diet is especially useful for teenagers of 13-15 years. 1-2 grammes of cod-liver oil a day are enough for immunity and prevention strengthening obesity.