Scientists trick bodies into 'Losing Weight' to uncover why diets fail

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Adolescents aged 12 to 16 (inclusive), at Tanner stage 3-5, with obesity defined as a body mass index (BMI) above the 97th percentile according to national growth charts. * No regular consumption of tobacco or alcohol, * No diet (no calorie restriction, no specific diet such as a normal-calorie diet enriched with protein, vegetarian, or other), * Adolescents affiliated with the social security system or equivalent, * Adolescent who has been informed and has given written consent to participate in the study, * Signed consent of both holders of parental authority (or one in the event of death, major incapacity, or withdrawal of parental authority). Exclusion Criteria: * Refusal to participate in the study, * Refusal of consent by parents or guardians, * Participation in regular and intense physical and sporting activities (no more than 150 minutes of moderate structured activity per week (according to WHO recommendations), * Medical or surgical history deemed by the investigator to be incompatible with the study, * Presence of diabetes or any other condition limiting the application of either strategy being tested, * Adolescents undergoing energy restriction or a weight loss program through physical activity at the time of inclusion or during the previous 6 months, * Taking medications that may interfere with the study results. * Adolescents with cardiovascular problems, i.e., subjects with a history of cardiovascular and/or neurovascular disease, as well as subjects with cardiovascular and/or neurovascular risk factors (excluding obesity/overweight). * Surgery in the previous 3 months, * Adolescents who are currently excluded from another study, * Pregnant or breastfeeding adolescents, * Adolescents under guardianship/curatorship or legal protection, * Parents under guardianship/curatorship or legal protection.