The Effect of Breast and Formula Feeding on Infant Obesity

Childhood obesity has emerged as a major global public health concern due to its increasing prevalence and the limited effectiveness of available treatment strategies. Consequently, greater emphasis has been placed on preventive approaches early in life, particularly infant feeding practices. This narrative review examines the impact of breastfeeding and formula feeding on infant and childhood obesity, with a focus on growth trajectories, body mass index development, and long-term metabolic outcomes from infancy through adolescence. A structured literature search was conducted using PubMed, Scopus, and Google Scholar databases to identify relevant studies published between 1980 and 2024, including meta-analyses, systematic reviews, cohort studies, and population-based observational studies. Evidence from multiple studies consistently suggests that breastfeeding is associated with a reduced risk of overweight and obesity during early childhood, potentially through mechanisms related to metabolic programming, adipose tissue development, and gut microbiome composition. However, findings across studies remain heterogeneous, and several analyses did not adequately adjust for important confounding factors such as parental body mass index. Overall, while breastfeeding appears to confer a protective effect against early excessive weight gain, its long-term impact on obesity risk remains inconclusive, highlighting the need for well-designed studies with appropriate control of confounding variables.