Effect of a Modified Ketogenic-Mediterranean Diet on Alzheimer's Disease

Inclusion Criteria: 1. Male or post-menopausal female; 2. Age 50 to 85 years inclusive; 3. Cognitive diagnosis ranged from cognitively normal for "'Healthy' and 'At-Risk'" to mild/moderate cognitive impairment for "MCI/eAD;" 4. Stable medical condition (generally 3 months prior to screening visit) at the discretion of study physician; 5. Stable on medications (generally 4 weeks prior to screening visit) at the discretion of study physician; 6. Able to complete baseline assessments; 7. HbA1c and fasting glucose within the normal (Healthy or MCI/eAD) or pre-diabetic (At-Risk or MCI/eAD) range depending on group. Exclusion Criteria: 1. Diagnosis of neurodegenerative illness (except for MCI or early AD in the MCI/eAD group); 2. History of a clinically significant stroke; 3. Current evidence or history in past year of focal brain lesion, head injury with loss of consciousness or DSM-IV criteria for any major psychiatric disorder including psychosis, major depression, bipolar disorder, alcohol or substance abuse; 4. Sensory impairment (i.e.: visual or auditory) that would preclude the participant from participating in the protocol; 5. Diabetes that requires current use of diabetes medications; 6. Current use of cholesterol/lipid lowering medications; 7. Clinically significant elevations in liver function tests; 8. Active neoplastic disease (stable prostate cancer and non-melanoma skin cancer is permissible); 9. History of epilepsy or seizure within past year; 10. Contraindications for MRI (claustrophobia, craniofacial metal implants, pacemakers); 11. Significant medical illness or organ failure, such as uncontrolled hypertension or cardiovascular disease, chronic obstructive pulmonary disease, liver disease, or kidney disease; 12. Use of the following medications: anticonvulsants, drugs with potential interfering CNS effects (other than cholinesterase inhibitors or memantine), medications with significant anticholinergic activity, anti-parkinsonian medications or regular use of narcotic analgesics; 13. If female, menstruation in the past 12 months or hysterectomy and current hormone replacement therapy medication; 14. Major digestive disorders, absorption issues, or surgeries that may be exacerbated by diet changes; 15. Untreated hypothyroidism or B12 deficiency; 16. Participants currently using resveratrol, CoQ10 (coenzyme Q10), coconut oil/other medium chain triglyceride-containing (ie: Axona) supplements, or curcumin will be excluded unless they are willing to discontinue them 2 weeks prior to the start of baseline visits and remain off for study duration.