Patient description: The patient is a 25-year-old man with type 1 diabetes confirmed with molecular analysis 7 years ago. He presents to the clinic with shortness of breath and fatigue during activities. He claims mild dyspnea after climbing 3 floors, no dyspnea at rest and no angina (New York Heart Association class 2). He is diagnosed with cardiomyopathy that will be treated with ACE inhibitors and Beta blockers. His takes 70/30 Insulin and vitamin D supplements. His past medical history is not significant for any other medical issues. His family history is positive for DM type 1 in his uncle and his grandfather. His lab study is as bellow: FBS: 100 mg/dl HbA1c: 6.5% Cholesterol: 190 mg/dl TG: 140 mg/dl LDL: 125 mg/dl HDL: 40 mg/dl

Clinical trial eligibility criteria: eligible ages (years): 8.0-25.0,  Obesity Overweight Diabetes Mellitus, Type 2 Type 2 diabetes mellitus as defined by: 1. Fasting blood glucose greater than or equal to 126 mg/dL OR postprandial blood sugar greater than or equal to 200 mg/dL (either during OGTT at NIH or as previously documented on outside medical record). 2. Since subjects may already have been started on treatment with hypoglycemic agents at the time of enrollment, they may have blood glucose levels in the impaired glucose tolerance range (fasting glucose 100-125 mg/dL and postprandial 140-199 mg/dL). This is a sign of adequately controlled diabetes, rather than an incorrect diagnosis of diabetes. Therefore, prior documentation (on outside medical records) of blood glucose values documenting diabetes will be acceptable if the subject has impaired glucose tolerance rather than overt diabetes according to screening results at NIH. 3. Absence of insulin autoantibodies (in insulin na(SqrRoot) ve patients only) Or 2. Clinical diagnosis of type 1 diabetes mellitus (for Pilot Study only) And 3. Age 8-25 years at enrollment  Normal OGTT at NIH (fasting blood glucose < 100 mg/dL AND 2 hour blood glucose < 140 mg/dL) 2. Significant comorbidity that, in the opinion of the investigators, will increase risk to the subject(specific obesity-related comorbidities are explicitly permitted, including hypertension, hyperlipidemia, obstructive sleep apnea and non-alcoholic steatohepatitis) 3. Positive urine pregnancy test 4. Psychiatric or cognitive disorder that will, in the opinion of the investigators, limit the subject's ability to comply with study procedures NON-DIABETIC Two types of volunteers will be recruited: 1. Overweight and obese volunteers who will be BMI matched with study enrollees who have T2DM during analyses 2. Normal weight (BMI between 5th and 85th centiles for age) volunteers Diabetes 2. Significant comorbidity that, in the opinion of the investigators, will increase risk to the subject (specific obesity-related comorbidities are explicitly permitted, including hypertension, hyperlipidemia, obstructive sleep apnea and non-alcoholic steatohepatitis) 3. Current use of drugs that alter glucose metabolism (e.g. metformin) 4. Current use of prescription or non-prescription weight-loss drugs 5. Positive urine pregnancy test 6. Psychiatric or cognitive disorder that will, in the opinion of the investigators, limit the subject's ability to comply with study procedures