Stage PRE formulas are especially formulated for the first 6 months of life. The term "PRE" has NOTHING to do with "preemie" or premature babies. These early stage formulas are ideal for supplementing, but are also completely fine for exclusive formula feeding in the first 6 months of life. The carbohydrate source in stage PRE formulas by HiPP and Holle is lactose, which is very easy to digest. When you start to notice that your little one is not as satiated from a bottle feeding as you'd like, you should consider switching to a Stage 1 formula until baby hits 6 month of age. Such stage 1 formulas incorporate "slower burning" carbohydrates like organic starch and maltodextrin.
