Heart failure is an ongoing epidemic of growing dimensions in western civilizations due to the increasing prevalence of the predisposing risk factors age, diabetes and obesity. Approximately one half of the patients have predominantly diastolic dysfunction (DD) and preserved left ventricular ejection fraction (HFpEF) with a prognosis that is just as unfavorable as systolic heart failure but with no known effective treatment. This stems from several factors, such as incomplete understanding of the underlying pathophysiologicalmechanisms and a lack of consensus on how to define and diagnose DD. All the known risk factors for DD and HFpEF such as age, hypertension, coronary artery disease, diabetes, insulin resistance, obesity, anemia, chronic obstructive pulmonary disease, sleep apnea and renal insufficiency are associated with insufficient availability of myocardial energy. The dominant impact of age on diastolic function E', as measured by tissue Doppler, requires as mathematical solution the comparison of the individually measured E' to a regression equation of Enorm over age from healthy individuals. This reference data allows the definition and the quantification of DD and the evaluation of age-independent structural, hemodynamic and metabolic risk factors for DD. This approach reveals the importance of metabolic risk and provides new options for therapy and for studies with well-defined inclusion criteria via the potential reversibility of insulin resistance.