A compound is provided from the group consisting of D-²-hydroxybutyric acid, acetoacetate and metabolic precursors of D-²-hydroxybutyric acid or acetoacetate which comprise moieties selected from the group consisting of (R)-1, 3-butandiol, acetoacetyl and D-²-hydroxybutyryl moieties and physiologically acceptable salts and esters thereof for use in treating an patient for diabetes, epilepsy, or an insulin resistant state.