The study objective is to evaluate whether a novel telemedicine-based intensive treatment program for children with obesity is superior to standard on-site care. This will be a randomized, non-blinded (due to the nature of the intervention) study, where 100 children and adolescents aged 10-18 years with obesity will be divided in a 1:1 ratio to either telemedicine or on-site treatments for 6 months. The telemedicine arm will include 30, mostly video, consultations for each participant: 3 physician appointments, 7 exercise consultations by our exercise physiologist, 10 dietary consultations by our pediatric dietitian, and 10 psychologist consultations to assist with goal setting and overall well-being. Three visits will be conducted in-office, for physician assessment, smartphone technical assistance and physical measurements (baseline, at 3 months and at the end of the 6-month period). Participants randomized to the telemedicine arm will have a step-counting rewarding app installed on their smartphone by our staff. The in-office arm will have 6 monthly visits during the study period, with two consultations performed in each visit - one by the physician or exercise physiologist, and one by our pediatric dietitian. The main outcome of the study is BMI standard deviation (z-score) changes, which will be evaluated after 3 and 6 months of treatment during physical office visits in both study arms. Secondary outcomes will be: * Body-fat percent changes, assessed by bioimpedance analysis in physical clinic visits. * Daily step counts, measured by smartphone data/ wearable activity tracker, if available. * Weight-related quality of life * Retention and visit cancellation rates. * Satisfaction of both parent and child from their allocated treatment.