Fasted Exercise Training in Type 1 Diabetes (FED-T1D)

Inclusion Criteria: 1. Clinical diagnosis of type 1 diabetes for 5 or more years. 2. Treatment using an insulin pump with no change in treatment modality for \> 2 continuous months and willing to share CGM data with the research team. Insulin delivery can be managed using either manual open-loop system (non-AID) or a hybrid closed loop (AID) systems. 3. Using rapid (e.g., Aspart, Lispro or Glulisine) or ultra-rapid (e.g., FiAsp) acting insulin analogs. 4. HbA1c 7.0-9.9%. 5. Have BMI of 25 kg/m2 or above 6. Have waist circumference associated with central obesity/metabolic syndrome as per Diabetes Canada definition * 94cm for males of European, Sub-Saharan African, Eastern Mediterranean and Middle Eastern descent * 90cm for males of South Asian, Chinese, Japanese, South and Central American descent * 80cm for females 7. No history of stroke, myocardial infarction, or coronary artery disease 8. Not wearing implantable device such as a pacemaker, neurostimulators, aneurysm clips, metal fragments, epicardial electrodes, cochlear implants, magnetic ocular implants, penile implants, magnetic tissue expander, some types of breast implants, magnetic orthopedic implants, magnetic dental implants, hearing Aids, intravascular implants, for example VCI filters, coils, stents, cardiac septum implants, ventricular bypass devices. 9. Use a CGM in routine diabetes management. Exclusion Criteria: 1. Major complication within the previous 3 months (e.g., severe hypoglycemia requiring assistance, diabetic ketoacidosis, or cardiovascular event). 2. Restriction in aerobic or resistance exercise due to significant diabetes complications (e.g., severe peripheral neuropathy, active proliferative retinopathy, etc.) or other type of limitations (e.g., orthopedic, severe arthritis, etc.). 3. Uncontrolled hypertension (e.g., blood pressure \>160 mmHg systolic or \>100 mmHg diastolic). 4. Implanted device, material, or having a condition contraindicated to MRI. 5. Ongoing pregnancy or breastfeeding. 6. Inability to give consent. 7. Use of an injection-based insulin therapy (ex. multiple daily injections or combined pump and injection-based delivery).