Neonates have high nutrient demands. Exclusive breastfeeding, an effective way to ensure child health and survival, is recommended for neonates within the first hour of birth and to be continued on demand for the first 6 months of life. However, exclusively breastfed neonates typically lose about 7% of their birth weight prior to beginning weight gain. Risk factors for inadequate neonatal growth may include low birth weight and weight loss greater than 5% at 4 days of age. 1,2 Different phenotypes of low birth weight such as preterm birth and intrauterine growth restriction may differ in nutrition requirements and response. While initial weight loss is often transient and may not have subsequent consequences in the majority of healthy term neonates, it may have serious consequences for more vulnerable, at-risk neonates, including those with low birth weight or who were born preterm, particularly in resource-constrained settings in Africa and Asia.When breastfeeding alone is not able to adequately meet a neonate's nutritional demands and energy requirements, growth faltering, wasting and stunting, and poor neurodevelopmental outcomes may occur, causing developmental problems that can persist into later childhood and beyond. Globally, more than 50 million and 150 million children younger than 5 years experience wasting and stunting, respectively, with the greatest burden in resource-constrained settings in Africa and Asia. These children have lower survival rates and high mortality from pneumonia, diarrhea, and other infectious diseases. Longer-term effects of wasting and stunting include small stature and low body mass in adulthood as well as diminished cognitive development, reduced productive capacity, poor health, and an increased risk of degenerative diseases such as diabetes. Preventing and expeditiously treating neonatal undernutrition are critical to addressing the burden of wasting and stunting worldwide. Providing supplemental feeding to at-risk neonates has the potential to provide additional nutrients and prevent undernutrition and subsequent wasting and stunting.However, supplemental feeding in the neonatal period should be implemented in a manner that sustains and supports long-term breastfeeding, which provides critical nutrition and health benefits to children through 2 years of age, including greatly reduced mortality. Nonexclusive breastfeeding has been associated with poorer growth outcomes when breast milk is displaced, or re-