A Scalable Nutrition Adherence Intervention

Objective 1: To scale-up the nutrition adherence intervention for testing in racially diverse rural communities in North Florida. The investigators hypothesize that: 1\. The protocol will produce at least 75% of participants obtaining measurable levels of urine ketones (e.g., good adherence) in the Modified Mediterranean-Ketogenic diet (MMKD) group and an average score of \>6 on the MEDAS questionnaire in the Mediterranean group during the 10-week program. Further, we hypothesize that the use of ongoing monthly support groups will bolster long-term adherence. Objective 2: To evaluate the effects of adherence to Mediterranean versus MMKD on novel gut-brain axis markers of Alzheimer's disease pathogenesis in individuals with mild cognitive impairment compared to cognitively normal older adults. The investigators hypothesize that individuals with mild cognitive impairment will: 1. Have greater evidence of gut dysbiosis at baseline than cognitively normal controls and 2. Will demonstrate greater increases in beneficial gut microbial metabolites in response to adherence to Mediterranean-Ketogenic nutrition and the Mediterranean diet compared to CN controls.

Inclusion Criteria: * Ages 55-85 * converted telephone MoCA total score: MCI = 17 ≤ 26, CN= ≥27 and/or and/or MCS MCI≥3, CN\ 20), alcohol or substance abuse, or disordered eating symptoms (SCOFF \> 2) * sensory impairment (visual or auditory) that might preclude participant from participating in the study * serious medical risk or organ failure, such as type 1 diabetes mellitus, recent cardiac event (e.g. heart attack, angioplasty) * prescribed Warfarin, insulin, or immunosuppressants * use of medications including anticonvulsants, drugs with potential interfering CNS effects (except cholinesterase inhibitors or memantine), and medications with known anticholinergic activity * a nut or fish allergy (does not include shellfish) * current use of highly restrictive or specialized diet regimen (e.g., vegan, use of MAOIs etc.) * major digestive disorders, absorption issues, or surgeries that could be exacerbated by dietary intervention * Non-English speaking.