Inclusion Criteria:  281 obese adolescents who participated in the randomized controlled interventional trial with low GI index diet Willingness to give written consent  Exclusion Criteria:  Subjects who are allergic to any ingredients listed in G-NiiB®, microbiome immunity formula. Subjects with any condition that the investigator deems as a sound reason (e.g. active gastrointestinal diseases and malignancies) for disqualification from enrollment into the study.