Inclusion Criteria:  HbA1c ≥6.0% for obese group BMI ≥ 95th %ile for obese group BMI ≥ 5 and <85th %ile for control group Type 1 diabetes (T1D) Antibody negative  Exclusion Criteria:  History of Chronic kidney disease (CKD) or acute kidney injury (AKI) Metabolic disorder prohibiting safe fasting Iodine or penicillin allergy Pregnancy Thrombophilia MRI contraindications Hormone therapy