Cocoa to Improve Walking Performance in Peripheral Artery Disease

Inclusion Criteria: 1. All participants will be age 60 and older. 2. All participants will have PAD. PAD will be defined as follows. First, an ABI \< 0.90 at baseline is an inclusion criterion for PAD. Second, potential participants with an ABI \> 0.90 who have vascular lab evidence of PAD or angiographic evidence of PAD will be eligible. Exclusion Criteria: 1. Above- or below-knee amputation. 2. Critical limb ischemia. 3. Wheelchair-bound or requiring a cane or walker to ambulate. 4. Walking is limited by a symptom other than PAD. 5. Baseline six-minute walk value of \<500 feet or \>1,600 feet 6. Lower extremity revascularization, major orthopedic surgery, cardiovascular event, or coronary revascularization in the previous three months. 7. Planned revascularization or major surgery during the next six months. 8. Major medical illness including renal disease requiring dialysis, lung disease requiring oxygen, Parkinson's disease, a life-threatening illness with life expectancy less than six months, or cancer requiring treatment in the previous two years. \[NOTE: potential participants may still qualify if they have had treatment for an early stage cancer in the past two years and the prognosis is excellent. Participants who require oxygen only at night may still qualify.\] 9. Mini-Mental Status Examination (MMSE) score \< 23 or dementia. 10. Unwilling to attend three visits in one week for final outcome measures. 11. Allergy to chocolate. 12. Unwilling or unable to consume products manufactured on the same equipment that processes peanuts, tree nuts, egg, wheat, soy, and milk. 13. Use of cocoa-containing dietary supplements. 14. Unwilling to give up major dietary sources of epicatechin during the study. 15. Symptoms of heart failure or angina that limit walking activity more than ischemic leg symptoms, increase in angina, or angia at rest (i.e. unstable angina). 16. Participation in or completion of a clinical trial in the previous three months. \[NOTE: after completing a stem cell or gene therapy intervention, participants will become eligible after the final study follow-up visit of the stem cell or gene therapy study so long as at least six months have passed since the final intervention administration. After completing a supplement or drug therapy (other than stem cell or gene therapy), participants will be eligible after the final study follow-up visit as long as at least three months have passed since the final intervention of the trial.\] 17. Non-English speaking, a visual impairment that limits walking ability. 18. In addition to the above criteria, investigator discretion will be used to determine if the trial is unsafe or not a good fit for the potential participant.