Renal Oxygen Consumption, Insulin Sensitivity, and Daily Caloric Restriction in ADPKD

Inclusion Criteria: * 18-65 years of age * ADPKD diagnosis based on the modified Pei-Ravine criteria * Body-mass index of 25-45 kg/m\^2 * Estimated glomerular filtration rate ≥ 30 mL/min/1.73m\^2 * Total kidney volume (htTKV) \> 600 mL, calculated from a previous kidney ultrasound or magnetic resonance imaging performed within the last 12 months * Access to the internet with video chat capabilities * No plans for extended travel (\>2 weeks) without internet access during the 12-month intensive period * Not currently participating in or planning to participate in any formal weight loss or physical activity program, or another interventional study * Ability to provide informed consent Exclusion Criteria: * Diabetes mellitus * Current smokers or history of smoking in the past 12 months * Alcohol dependence or abuse * History of hospitalization or major surgery within the last 3 months * Untreated dyslipidemia * Uncontrolled hypertension * Pregnancy, lactation, or unwillingness to use adequate birth control * Cardiovascular disease, peripheral vascular disease, or symptoms suggestive of cardiovascular disease: chest pain, shortness of breath at rest or with mild exertion, syncope * Abnormal resting electrocardiogram (ECG): serious arrhythmias, including multifocal premature ventricular contractions (PVC's), frequent PVC's (defined as 10 or more per min), ventricular tachycardia (defined as runs of 3 or more successive PVC's), or sustained atrial tachyarrhythmia; 2nd or 3rd degree A-V block, QTc interval \> 480 msec or other significant conduction defects * Significant pulmonary disease including: chronic obstructive pulmonary disease, interstitial lung disease, cystic fibrosis, or uncontrolled asthma * Regular use of prescription or over-the-counter medications that may affect weight, appetite, food intake, or energy metabolism * History of clinically diagnosed eating disorder including: anorexia nervosa, bulimia, binge eating disorder * Weight loss of \>5% in the past 3 months for any reason except post-partum weight loss; weight gain \>5% requires assessment by PI * Major psychiatric disorder (e.g., psychosis, schizophrenia, mania, bipolar disorder) or current severe depression, based on DSM-IV-TR criteria for Major Depressive Episode, which in the opinion of the Study MD would interfere with ability to adhere to dietary interventions) * Inability to cooperate with or clinical contraindication for magnetic resonance imaging, including: severe claustrophobia, implants, devices, or non-removable body piercings * Previous obesity treatment with surgery or weight loss device, except: (1) liposuction and/or abdominoplasty if performed \> 1 year before screening, (2) lap banding if the band has been removed \> 1 year before screening, (3) intragastric balloon if the balloon has been removed \> 1 year before screening (4) duodenal-jejunal bypass sleeve, if the sleeve has been removed \> 1 year before screening or 5) AspireAssist or other endoscopically placed weight loss device if the device has been removed \> 1 year before screening.