Freeze-drying is a very gentle process, and results in retention of the nutrients in breast milk. Various human milk donor banks world-wide are implementing this process as an improved method of storage for donated breast milk. We have more information about the research of how the freeze-drying process affects various components of breast milk here and here. From extensive testing of our process, we have seen similar results to what is published in the research cited on our site – no significant decline in any macronutrients (proteins, fats, carbs, or overall caloric content). We now offer nutritional testing as an add-on to our service in which we measure the calories, carbohydrates, fats, and proteins in your milk using the Miris, an FDA approved human milk analyzer. When rehydrated according to the instructions on the custom label of each pouch - the rehydrated breast milk will have the same nutritional composition as before freeze-drying. Please contact us to ask about how you can receive this analysis with your order!