Effects of Ketone Monoesters on Brain Function

Inclusion Criteria: * Men, aged between 60-75 years * BMI between 25-30 kg/m2 * Fasting plasma glucose \< 7.0 mmol/L * Fasting serum TC \< 8.0 mmol/L * Fasting serum TAG \< 4.5 mmol/L * Systolic blood pressure \< 160 mmHg and diastolic blood pressure \< 100 mmHg * Stable body weight (weight gain or loss \< 3 kg in the past three months) * Willingness to give up being a blood donor from 8 weeks before the start of the study, during the study and for 4 weeks after completion of the study * No difficult venipuncture as evidenced during the screening visit Exclusion Criteria: * Women * Left-handedness * Following a low-carbohydrate diet or consuming nutritional ketone supplements * Current smoker, or smoking cessation \< 12 months * Diabetic patients * Familial hypercholesterolemia * Abuse of drugs * More than 3 alcoholic consumptions per day * Use of products or dietary supplements known to interfere with the main outcomes as judged by the principal investigators * Use medication to treat blood pressure, lipid or glucose metabolism, or neurological or mental disorders. * Use of an investigational product within another biomedical intervention trial within the previous 1-month * Severe medical conditions that might interfere with the study, such as epilepsy, asthma, kidney failure or renal insufficiency, chronic obstructive pulmonary disease, inflammatory bowel diseases, auto inflammatory diseases and rheumatoid arthritis * Active cardiovascular disease like congestive heart failure or cardiovascular event, such as an acute myocardial infarction or cerebrovascular accident * Contra-indications for MRI imaging (e.g. pacemaker, surgical clips/material in body, metal splinter in eye, claustrophobia).