Inclusion Criteria:

• * A confirmed clinical diagnosis of stable HFpEF on maximally tolerated Heart Failure (HF) medical regimen (without changes in dosage in the prior month)
• * Left ventricular ejection fraction of \>50% documented in the prior 12 months
• * A confirmed clinical diagnosis of Type II diabetes (T2DM) with glycated hemoglobin \<10% without changes in medical regimen in the past month.

Exclusion Criteria:

• * Current usage of pre- or probiotic usage
• * Antibiotic usage in the past 6 months
• * Current participation in another interventional clinical trial
• * History of potato allergy or potato starch allergy, inflammatory bowel syndrome, inflammatory bowel disease, bowel resection, Roux-en-Y gastric bypass surgery, celiac disease, Crohn's disease, or colorectal cancer
• * Hypoglycemic episode with blood glucose 70 milligrams per deciliter (mg/dL) within the last month
• * Stage IV-V chronic kidney disease
• * Pregnancy (self-reported)
• * Comorbidity limiting survival to \< 12 months