Level Up! (The Combined and Independent Effects of Exercise Training and Dietary Enhancement on Cardiometabolic Health in Adolescents With Obesity)

The Level Up! study is a 12-week randomized controlled trial designed to investigate the independent and combined effects of exercise training and dietary enrichment on cardiometabolic health in adolescents with obesity. The study will enroll adolescents participating in an obesity treatment program. Participants will be randomly assigned to one of four groups: standard of care, exercise, dietary, or combined exercise and dietary intervention. Each participant will attend three assessment visits at baseline, week 6, and week 12 at the Arkansas Children's Nutrition Center (ACNC). The following key measurements will be conducted: * Body Composition: Dual-Energy X-ray Absorptiometry (DXA) * Metabolic Profile: Fasting blood markers, including glucose, lipid profile, and insulin resistance * Vascular Function: Brachial artery flow-mediated dilation (ultrasound) * Liver Fat Content: Elastography * Continuous Glucose Monitoring: Interstitial sensor-based glucose measurement * Resting Metabolic Rate: Indirect calorimetry * Aerobic Capacity: Cardiopulmonary exercise test (spirometry) * Muscle Strength: Dynamometry * Physical Activity \& Sleep: Accelerometry * Dietary Intake: 3-day food records