How does the addition of a fat modular to increase caloric density affect osmolarity?

• A. Will increase osmolarity.
• B. Will not impact osmolarity.
• C. Will decrease osmolarity.
• D. Causes large fluctuations in osmolarity.

Answer: (B)

Osmolarity depends on the number of osmotically active particles in the aqueous phase. A fat module delivers fat in an emulsion form, which stays as a separate lipid phase and does not add solute particles to the watery portion of the solution. In practice, lipid emulsions are used to raise calories without increasing the solution’s osmolar load, so the osmolarity remains essentially unchanged. If you were increasing osmolarity, you’d be adding more soluble particles like dextrose or amino acids; decreasing or fluctuating osmolarity would require removing solutes or altering the balance of solutes, which isn’t what adding a fat module does.