In this study, the investigators aimed to observe changes in the gut microbial composition before and after the weight-loss intervention, including dietary control and exercise, in obese children. The main metabolites produced by gut microbiome, short chain fatty acids (SCFAs) will be also analysed. The investigators will analyse the change of gut microbiome composition and metabolites related with weight-loss intervention and the relationship between microbiome composition and metabolites.

Many recent studies have suggested that dysbiosis of the gut microbiome might related to obesity. There is growing evidence that the composition of gut microbiome changes in childhood obesity compared to normal-weight children, and it is attracting attention as an adjustable environmental factor in obesity treatment. It has been reported that gut microbiome could be changed due to environmental influences such as diet and exercise. In this study, the investigators aimed to observe changes in the gut microbial composition before and after the weight-loss intervention, including dietary control and exercise, in obese children. The main metabolites produced by gut microbiome, short chain fatty acids (SCFAs) would be also analysed to investigate the relationship with gut microbiome and with weight-loss intervention. Intervention is not performed for normal-weight children, and samples from normal-weight children will be used as a control for gut microbiome and biochemical tests.

Inclusion Criteria:

• Obese children: Children ≥95 ‰
• Non-obese children: 5‰\

Study participants will only agree if IPD is not shared.