Bone Metabolism in 12-21 Year Olds Undergoing Glucagon Like Peptide (GLP)-1 Receptor Agonist Therapy

The goal of this clinical trial is to compare bone health markers over 24 months in participants 12 - 21 years of age with obesity who are starting the glucagon-like peptide-1 receptor agonists (GLP-1RAs) as compared to those with similar weight followed by lifestyle management. Participants will: * Take GLP-1RA as prescribed or continue to work on lifestyle management for weight loss * Take provided calcium and vitamin D supplements * Attend 6 study visits over 24 months with two at the beginning and then every 6 months that include: * History and Physical Exams * Lab Work * Imaging studies * Questionnaires * 24-hour dietary recalls