Abstract: Use of a compound having the formula (1) (2) (3) or (4) or combinations thereof, for increasing blood ketone levels, and/or treating a disease treatable by increasing blood ketone levels, preferably wherein the disease is selected from the list consisting of: a brain energy deficiency condition, a neurological condition, migraine, memory disorder, age-related memory disorder, brain injury, stroke, amyloid lateral sclerosis, multiple sclerosis, cognitive impairment, cognitive impairment post-intensive care, age-induced cognition impairment, Alzheimer's disease, Parkinson's disease, Huntingdon's disease, inherited metabolic disorders (such as glucose transporter type 1 deficiency syndrome and pyruvate dehydrogenase complex deficiency), depression, schizophrenia, epilepsy, narcolepsy, diabetes, obesity, non-alcoholic fatty liver disease and polycystic ovary syndrome, wherein R1, R2, R3, R4, R5 and R6 are independently a long chain fatty acid having between 16 and 20 carbons.