INTRODUCTION: Preterm and low birth weight (LBW) infants are at an increased risk of morbidity and mortality compared with their term counterparts, with more than 20 million LBW infants born each year, the majority in lower middle-income countries (LMICs). Given the increased vulnerability and higher nutritional needs of these infants, optimizing feeding strategies may play a crucial role in improving their health outcomes. METHODS: We updated evidence of Every Newborn Series published in The Lancet 2014 by identifying relevant systematic reviews, extracting low-income country (LIC) and LMIC data, and conducting revised meta-analysis for these contexts. RESULTS: We found 15 reviews; the evidence showed that early initiation of enteral feeding reduced neonatal mortality overall, but not in LIC/LMIC settings. Breastfeeding promotion interventions increased the prevalence of early initiation of breastfeeding and exclusive breastfeeding at 3 and 6 months of age in LMIC settings. There was an increased risk of neonatal mortality with formula milk in LIC/LMIC settings. Despite contributing to greater weight gain, there was a higher risk of necrotizing enterocolitis with formula milk overall. Breast milk fortification and nutrient-enriched formula improved growth outcomes. Iron and vitamin A supplementation reduced anemia and mortality rates (LMIC), respectively. The evidence also suggested that benefits of various different micronutrient supplementation interventions such as zinc, calcium/phosphorous, and vitamin D, outweigh the risks since our review demonstrates little to no adverse effects deriving from their supplementation, particularly for a breastfed preterm and/or LBW infant. CONCLUSION: Early adequate nutritional support of preterm or LBW infant is paramount to averse adverse health outcomes, contribute to normal growth, resistance to infection, and optimal development. Breast milk feeding and micronutrient supplementation are crucial to reduce diarrhea incidence and mortality respectively while feed fortification or nutrient-enriched formula, when breast milk is not available, to enhance better growth especially in LMICs where there is higher population of growth restriction and stunting. This review also highlights need for randomized trials in LMICs at large scale to further strengthen the evidence. INTRODUCTION: Preterm and low birth weight (LBW) infants are at an increased risk of morbidity and mortality compared with their term counterparts, with more than 20 million LBW infants born each year, the majority in lower middle-income countries (LMICs). Given the increased vulnerability and higher nutritional needs of these infants, optimizing feeding strategies may play a crucial role in improving their health outcomes. METHODS: We updated evidence of Every Newborn Series published in The Lancet 2014 by identifying relevant systematic reviews, extracting low-income country (LIC) and LMIC data, and conducting revised meta-analysis for these contexts. RESULTS: We found 15 reviews; the evidence showed that early initiation of enteral feeding reduced neonatal mortality overall, but not in LIC/LMIC settings. Breastfeeding promotion interventions increased the prevalence of early initiation of breastfeeding and exclusive breastfeeding at 3 and 6 months of age in LMIC settings. There was an increased risk of neonatal mortality with formula milk in LIC/LMIC settings. Despite contributing to greater weight gain, there was a higher risk of necrotizing enterocolitis with formula milk overall. Breast milk fortification and nutrient-enriched formula improved growth outcomes. Iron and vitamin A supplementation reduced anemia and mortality rates (LMIC), respectively. The evidence also suggested that benefits of various different micronutrient supplementation interventions such as zinc, calcium/phosphorous, and vitamin D, outweigh the risks since our review demonstrates little to no adverse effects deriving from their supplementation, particularly for a breastfed preterm and/or LBW infant. CONCLUSION: Early adequate nutritional support of preterm or LBW infant is paramount to averse adverse health outcomes, contribute to normal growth, resistance to infection, and optimal development. Breast milk feeding and micronutrient supplementation are crucial to reduce diarrhea incidence and mortality respectively while feed fortification or nutrient-enriched formula, when breast milk is not available, to enhance better growth especially in LMICs where there is higher population of growth restriction and stunting. This review also highlights need for randomized trials in LMICs at large scale to further strengthen the evidence.