I will look into this further--I don't have the resources at home to check the literature plus I will ask a GI colleague and a neonatology colleague. However, re: the subject of mixing formula with less than normal amount of water to make up 24cal/oz out of powder designed for 20cal/oz--I have seen it recommended from some well respected places (I think either UCIrvine or CHOC--Children's Hosp of Orange County, both in California) probably because it is cheaper than 24cal formula, and what I need to check into is whether there are any reports in the literature about problems with it. Potential problem issues: 1. increased salt load and decreased water supply, possibly leading to hypernatremia (high blood sodium or salt) 2. increased solute load (overload on kidneys) 3. increased osmotic load (too many particles in liquid going through gut) potentially leading to diarrhea. The commercial 24cal formula that is now available designed for premies has a normal salt content, normal (I think) water content, normal solute load, normal (isotonic) osmotic load. I'll check some references (people and journals) and recomment tomorrow.