At birth a newborn can only taste 3 of the 4 major taste categories (sweet, sour and bitter). Before 4 months, babies don’t show much reaction to the forth category - salt; however, after 4 months, babies have developed the nerve cells needed to detect salt in liquids. You will notice that a baby typically shows a preference for sweet liquids and sweet tasting foods. It is interesting to note that babies actually need natural occurring sugars in their diets. Natural sugars are extremely important for proper brain growth and development in a young child until about 2 years of age.