To meet the nutrient demands for infant growth, the first solid food offered should be an iron-fortified infant cereal (oat-based), mixed with breast milk or infant formula, and fed with a spoon. Parents are then advised to introduce solid foods one at a time (rather than in the form of food mixtures or infant dinners). Ideally, new foods should be spaced out by about three to five days, in order to watch for any food intolerances or allergic reactions. Smooth purees are initially recommended to help ease a baby into eating solid foods. Once a baby has mastered purees, food textures can be increased slowly and steadily by blending food into coarser purees, then moving on to chunkier and lumpier textures, and finally progressing to fork-mashed and soft finger foods. Cooked foods, such as French fry-sized pieces of manes, melons, and cucumbers, may also be offered for a baby to gnaw on as soon as he or she is able to sit without assistance and pick up food independently.