Brain Health in Youth With Normal Weight, Overweight and Obesity at Risk for Type 2 Diabetes (T2D)

Inclusion Criteria: * 12-17 yrs. old at visit 1, 12-19 yrs. old at visit 2, Tanner II or above (determined through an exam by a pediatric endocrinologist or certified nurse practitioner trained in pediatric endocrinology), otherwise healthy except for obesity, \<450 lbs. (due to MRI scanner limits), able and willing to lie flat within the MRI scanner and do cognitive testing, fluent in English. Exclusion Criteria: * Syndromic obesity, history of bariatric surgery, insulin treatment (metformin allowed if \< 6 months) for T2D, contraindications for MRI (metal, claustrophobia), braces, pregnant (pregnancy test will be done on post-menarchal girls) or breastfeeding, inability to participate in cognitive testing due to sensory or language issues, intellectual disability, special education, pharmacologic treatment for Attention Deficit Hyperactivity Disorder (ADHD), prematurity (\<36 weeks gestation), complications at birth, neurologic co-morbidities (e.g., seizures, stroke, head injury with \>10 min loss of consciousness), significant psychiatric disorders (e.g., schizophrenia, bipolar disorder, current major depression), taking psychoactive medications (e.g., antipsychotics) that would interfere with testing or reporting illegal drug use. Self-reported smoking and alcohol use and length of time with obesity will be assessed by history (although these measures may not be fully reliable).