A two months intervention in which two groups of cognitive disorders, Parkinson and Alzheimer's disease, will receive 50g/day of a commercial MCT supplement combined with supervised aerobic exercise 3 times/week. Cognition and ketones will be assess before and after the intervention, along with endocannabinoids plasma concentrations.

Inclusion Criteria:

• Alzheimer's or parkinson disease diagnostic
• Stable medication associated with the disease
• Able to consent
• Presence of an accompanying person for the first and last visit.
• Ability to read and talk in French

Exclusion Criteria:

• MMSE < 20
• MCT or coconut oil supplementation
• Coconut allergy
• Cannabis, THC or CBD consumption
• Excessive alcohol consumption
• Physical activity 3x/week
• Presence of an metallic object in the body
• Impossibility to lay in dorsal decubitus for 40 minutes
• Cardiac disease
• Any uncontrolled disease that could interfer with the project.