BackgroundObesity can cause structural changes and functional adjustments in growing children’s feet. However, there is a lack of continuous observation of changes in feet in children with persistent obesity during important developmental periods. This makes it challenging to provide precise preventive measures. ObjectiveThis study aimed to investigate the effects of persistent obesity on gait patterns in children at an important stage in the formation of a robust foot arch. MethodsThe Footscan® plantar pressure system was used for 3 checks over two years. A total of 372 children aged 7–8 years participated in the study, and gait data from 33 children who maintained normal weight and 26 children with persistent obesity were finally selected. Repeated measures ANOVA or Friedman’s test were used for longitudinal comparisons. Independent-Sample t-tests or the Mann-Whitney-Wilcoxon tests were used for cross-sectional comparisons. ResultsDuring the important period of development, children with persistent obesity did not exhibit a significant decrease in the arch index and had significantly higher values than the normal group in the third check. The persistently obese children showed increased load accumulation in the lateral rearfoot, first metatarsophalangeal joints, and the great toe regions. Children with persistent obesity had significantly greater medial-lateral displacements in the initial contact phase and forefoot contact phase than normal children in the first check. These differences diminished between the second and third checks. SignificancePersistent obesity during an important period of foot development leads to slow or abnormal development of arch structure and affects foot loading patterns with heel inverted and forefoot everted. Additionally, the development of gait stability is not limited by persistent obesity.