The purpose of this study is to compare the effects of a well-formulated ketogenic diet with a low-fat diet on exercise tolerance in patients with heart failure and diabetes or pre-diabetes or metabolic syndrome.
- Age ≥ 18 years old and ≤ 80 years old & willingness to be randomized to either diet.
- NYHA class I – III for at least 3 months.
- Ejection fraction ≥50% by biplane 2D, or 3D echo, or CMR
- Echo findings of abnormal or indeterminant diastolic function or RHC data: At rest: mean pulmonary capillary wedge pressure (PCWP) > 15 mmHg. pulmonary vascular resistance (PVR) < 3 Wood Units.
- Stable medical therapy for at least 3 months as determined by the treating physician (no new cardiac or diabetic medications within 3 months of enrollment or during enrollment and dosage should be stable for 1 month prior to enrollment).
- Dose of oral diuretics changes allowed but must be stable for 1 week prior to randomization.
- Body Mass Index (BMI) ≥ 25 and ≤ 50 or Type 2 Diabetes Mellitus or prediabetes (fasting glucose of 100 - 125 mg/dL or hemoglobin A1C 5.7-6.4%) or metabolic syndrome.
- Ability to participate in exercise treadmill testing.
- Ability to sign written consent.
- Women who are pregnant, current breast-feeding, or have intention to become pregnant while in the study.
- Known allergy or sensitivity to gadolinium-based contrast agents.
- Implanted pacemaker, cardioverter defibrillator, Cardiac resynchronization therapy, left ventricular assist devices.
- Other metallic implants/aneurysm clips that are contraindicated in MRI.
- History of severe kidney disease of eGFR<30 ml/kg/1.73m2.
Exclusion Criteria varies, please contact Study Coordinator.