Unsaturated Fatty Acids to Improve Cardiorespiratory Fitness in Obesity and HFpEF

The study will evaluate participant's food consumption during 2 different 12-week periods. During one of the 12-week periods, participants will receive specific counseling and instructions on how to increase the consumption of food rich in healthy fats; during the other 12-week period they will receive general dietary recommendations following the Dietary Guidelines for Americans. There will be a 6-week break (washout) between the 12-week periods for a total of study period of 30 weeks. During each 12-week periods, the study will measure the effects of these dietary recommendations on dietary consumption and the fatty acids in their blood (primary endpoints).

Major Inclusion Criteria:

• Body Mass Index (BMI) ≥30 kg/m2 (obesity) or total body fat percentage >25% in men and >35% in women
• A confirmed clinical diagnosis of stable HF (New York Heart Association (NYHA) class II-III) on maximally tolerated heart failure (HF) optimal medical regimen (without major changes in the prior month)
• Left Ventricular Ejection Fraction (LVEF)>50% documented in the prior 12 months

Major Exclusion Criteria:

• Concomitant conditions or treatment which would affect completion or interpretation of the study (i.e.,physical inability to walk or run on treadmill);
• Significant ischemic heart disease, angina, uncontrolled arterial hypertension, atrial fibrillation, moderate to severe valvular disease, chronic pulmonary disease, anemia (Hemoglobin<10 g/dL)
• Electrocardiography (ECG) changes (ischemia or arrhythmias) that limit maximum exertion during cardiopulmonary exercise test
• Comorbidity limiting survival
• Stage IV-V kidney disease (estimated Glomerular Filtration Rate<30)
• Fluid overload
• Pregnancy
• Current use of unsaturated fatty acids (UFA) supplement (i.e., omega-3).
• Inability to give informed consent