BackgroundChildhood obesity rates have reached epidemic levels with Mediterranean countries reporting among the highest numbers globally. Evidence suggests early life factors, including infant growth rate, increase the likelihood of obesity later in childhood. However, optimal rates of infant growth associated with lower odds of future obesity still remain undetermined. The study aim was to determine the optimal infant growth rate associated with a lower likelihood of childhood overweight and obesity.MethodsPerinatal and anthropometric data collected from 1778 Greek preschool (2–5 years old) and 2294 Greek preadolescent (10–12 years old) children participating in the ToyBox and the Healthy Growth Study (HGS) respectively, was combined for examination. Logistic regression models and receiver operating curves were used to determine the association between infant growth rate and development of childhood overweight and obesity, as well as optimal infant growth rate, respectively.ResultsRapid weight gain during the first 6 months of life was positively associated with overweight and obesity in preadolescent children (OR:1.36, 95% CI: 1.13–1.63). Optimal cut-off points for several infancy growth rate indices (i.e., WAZ, WLZ, HAZ, BAZ) associated with a lower likelihood of overweight and obesity in preschool years and preadolescence were also identified.ConclusionsThe current findings could possibly set the basis for healthcare professionals and families to better monitor, assess, and control infant growth rates, thus providing another obesity prevention strategy from early life. These findings, however, and the recommended optimal cut-offs need to be confirmed through further prospective research.