The FibreGum Study - Changing the Course of Obesity in Children

Inclusion Criteria: * Informed Consent according to International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use/Good Clinical Practice (ICH/GCP) regulations prior to any study specific procedures * Obesity as determined by a BMI ≥97th percentile using the Swiss paediatric, age- and sex-matched growth charts * Newly referred within the last month to a tertiary weight management clinic * Participant willing to use the study specific monitoring app on his/her own or legal representatives' smartphone Exclusion Criteria: * Antibiotic administration in the last 6 months * Pre- or probiotic treatment in the last 6 weeks * Any professionally supervised treatment for weight management within the last year * Consumption of more than one nicotine product per month (e.g. cigarette, gum) * Adolescent females: any stages of known pregnancy or lactation period * Congenital disorder affecting the cardiovascular, hepatic or respiratory system in a relevant way (as per PI's or specialist's evaluation) * Malignant disease on treatment or previous tumour affecting the appetite system (e.g., suprasellar, hypothalamic tumours) * Systemic antibiotic or anti-inflammatory medication (e.g. systemic intake of glucocorticoids) over the last 7 days * Known eating disorder (medically diagnosed) * Participation in another investigation with an investigational drug within the 30 days preceding and during the present investigation * Dependency from the sponsor or the clinical investigator * Inability to follow the procedures of the investigation, e.g. due to language problems, psychological disorders, etc. of the participant and/or legal representative