The major goal of this proposal is to characterize the ability of epicatechin which a component of dark chocolate to improve the

1. structural and functional features of skeletal muscle (SkM)
2. exercise capacity (as assessed by VO2 max)
3. parameters of diastolic heart function (as assessed by echocardiography)

We propose that a 3 month treatment with epicatechin (through CocoaVia® capsules) will lead to a significant improvement in exercise capacity and diastolic function.

Patient Inclusion/Exclusion Criteria:

1. New York Heart Association Class II/III HF with preserved ejection fraction (EF) of >50%.
2. Nonsmokers
3. Subject not taking Coumadin, Xarelto, Prasugrel or Pradaxa. Patients on Plavix for drug eluting stent will not be excluded.
4. Ages between 40-65. We will exclude any women of child bearing potential

Inclusion Criteria:

• Medically Diagnosed Heart Failure with Ejection Fraction of >55%
• BMI 27-32
• No Significant HbA1C fluctuations in past 6 months

Exclusion Criteria:

• Smoking or quit smoking less than 1 year prior to enrollment
• Substance Abuse
• Taking Coudmadin or Pradaxa