Abstract
The infant gut microbiome undergoes a crucial transformation when solid foods enter the diet during weaning. This introduction normally happens at about six months post-birth and leads to major shifts in the gut microbiome. Many of the changes that occur during this period are known to persist into adulthood. While many perinatal factors, including gestational age, delivery mode, feeding choices, and antibiotic exposure, strongly influence microbiome composition and functional trajectories, the effects of weaning, in particular, have received far less attention. This review examines the response of the microbiome ecosystem when the diet is radically altered through the introduction of solid foods during the weaning phase. This response involves major reshaping of anabolic and catabolic functioning, along with changes in bacterial taxa and increased diversity. The information presented in this review aims to fill existing knowledge gaps while advancing our comprehension of how the infant diet shapes gut microbiome development through childhood.