In preterm and Small for Gestational Age (SGA) infants, catch up growth is associated with neurocognitive benefits. However, it also carries a potential long-term impact on cardiometabolic health. Low Birth Weight (LBW) and SGA infants have increased energy needs. Increased protein intake is also required for catch up growth. Without adequate protein, catch up growth will not occur or will be delayed. For this reason, high protein feeds or protein-fortified human milk are usually given to such infants in the postnatal setting. In this presentation, Professor Ziegler provides an overview of the differences in basic nutritional needs of SGA infants. He also described the Factorial Approach to determine nutrient requirements.