This letter has been written by the components of the European Milk Bank Association (EMBA) Working Group on Human Milk Fortification in response to a recent paper published by Mathes et al. (BMC Pediatr. 2018 May 8;18(1):154) with the aim of drawing attention to the importance of the use of a metabolic marker to adapt protein intake in preterm infants. EMBA Working Group on Human Milk Fortification clarifies further the terminology and some specific aspects regarding individualized human milk fortification. There are two types of individualized human milk fortification: Adjustable human milk fortification and Targeted human milk fortification. Advantages and disadvantages of these methods are summarized.