The need of better labelling of fats in processed animal origin products is urgent. The lack of information makes it possible to exclude n-3 fatty acids in preparations of foods. The higher fat content, the higher n-6/n-3 ratio seems to be a rule. It is desirable to broaden the labelling into which oils have been used when foods are processed. The dietary balance of n-6 and n-3 fatty acids is important for homeostasis and normal development in humans. The ratio between n-6/n-3 fatty acids suggested to be evolutionary developed is between 1 and 4. The main conclusion is that the fat sources used during processing and preparation of convenient foods have the largest impact on the food FA content and composition. A proposal is therefore that this should be declared on the product label especially the n-3 FA content. It is also of large importance to increase consumption of freshwater fish fed suitable feeds containing n-3 fatty acids in central Europe to enable a generally lower n-6/n-3 ratio in the human diet. Therefore optimizing feeds to freshwater fish in culture is urgent and important., J. Picková., and Obsahuje seznam literatury