Phosphate Metabolites in Brain of Humans Aged 50+

Inclusion Criteria: * Men and women aged between 50 and 75 years * Healthy, based on the medical screening visit * Normal BMI for age (18.5-29.9 kg/m2) * Able to understand and to sign a written informed consent prior to trial entry * Informed consent signed Exclusion Criteria: * Known type 1 or type 2 diabetes, on anamnesis * Family history of type 2 diabetes (parents) * Any other metabolic disease possibly impacting the postprandial glucose and insulin response (on anamnesis, to the opinion of the medical expert) * Malabsorptive disorders including but not limited to pancreatitis, Crohn's disease, etc, to the opinion of the medical expert * Any ongoing medication impacting dietary fat absorption and metabolism like statins, bile acid sequestrants, lipid lowering medications, or fibrates , to the opinion of the medical expert * Any ongoing medication impacting the postprandial glucose and insulin response (like beta blockers), to the opinion of the medical expert * Any ongoing medication impacting brain metabolism or function (neuroleptics, antidepressants, anti-epileptics), to the opinion of the medical expert * Ongoing chemotherapy * Any food supplement intake (e.g. MCT, ketone salts = Calcium, Sodium, Potassium, Magnesium) or special diet (e.g. ketogenic diet) possibly impacting basal ketone levels, to the opinion of the medical expert. * Claustrophobia * Hearing disorders (the participant placed into the MRS tunnel should be able to hear from the operators, for safety purpose) * Having any metallic, electronic, magnetic, or mechanical implants, devices, or objects, for safety reason linked to magnetic field exposure (MRS): * Aneurysm clip(s) * Cardiac pacemaker * Implanted cardioverter defibrillator (ICD) * Electronic implant or device * Magnetically-activated implant or device * Neurostimulation system * Spinal cord stimulator * Cochlear implant or implanted hearing aid * Insulin or infusion pump * Implanted drug infusion device, like portacath® for instance * Any type of prosthesis or implant * Artificial or prosthetic limb * Any metallic fragment or foreign body * Hearing aid * Other implant * Subject injured by a metallic object or foreign body * Allergy to cow milk or soy proteins * Currently participating or having participated in an investigational trial during the past month * Subjects not willing and/or not able to comply with scheduled visits and the requirements of the research protocol. * Subject having a hierarchical link with the investigator or co-investigators.