Number of particles , not the mass of the solute in a solution determines its osmotic pressure. Solutions of equal osmolarity exert equal osmotic pressure. The measured osmotic pressure for a solution would Therefore not measure its true tendency to cause osmosis. TBW is variable and depends mostly on the fat in the body. Pool size is constant but turnover is Increased.
Metabolic water comes from combination of hydrogen and oxygen at end of electron transport chain.
This is also point at which oxygen is consumed by the body. Yield of water is greater for fat than protein or carbohydrate. 3. 100 g of fat yields 110 ml of water.