Abstract: The present invention provides a new fat mixture for infant and adult nutrition which possesses adequate levels and ratios of polyunsaturated fats and long chain polyunsaturated fats. These fat mixtures possess adequate levels of phospholipids and an adequate relationship between oleic acid, linoleic acid and .alpha.-linolenic acid as well as adequate levels of long chain polyunsaturated fatty acids of both the n6 and n3 series. In addition, the fat mixtures of the present invention possess an adequate ratio of arachidonic acid (20:4n6) to docosahexaenoic acid (22:6n3). These fat mixtures are modeled on the fat content of human milk for infant diets and on the mediterranean diet for adult nutritional products. Diets containing these mixtures promote the growth and development of the infant and contribute to the prevention and treatment of some diseases in adults.