Mediterranean Diet, Exercise and Dementia Risk in UK Adults

Inclusion Criteria: * Male and female, aged 55-74 years * Understands and is willing and able to comply with all study procedures, including changes to diet and physical activity levels * Access to, and able to use, the internet/computer/tablet device * QRISK3 score of \>=15 (assessed by GP) * Subjective Memory Complaints (SMC), based on a score of \>16 on the Cognitive Change Index (CCI) (from the first 12 items) * Stable use of any prescribed medication for at least four weeks * Normal (or corrected to normal) vision and hearing * Fluent in written and spoken English * Willing and able to provide written informed consent Exclusion Criteria: * Diagnosis of Alzheimer's disease (AD), other form of dementia, Mild Cognitive Impairment (MCI), or significant neurological disorder * Cognition not within normal range, based on a score of \<26 on the Montreal Cognitive Assessment (MoCA); or an indication of cognitive decline, based on a score of ≥2 on Ascertain Dementia (AD-8) * Evidence of impairment of Instrumental Activities of Daily living (IADLS) * Moderate to severe depression, assessed by the Patient Health Questionnaire (PHQ-9), a score of \>10 being exclusionary * Moderate to severe anxiety, assessed by the Generalised Anxiety Disorder Assessment (GAD-7), a score of \>10 being exclusionary * Current psychotic illness (delusional disorder/schizophrenia) * History of serious mental illness know to affect cognition (schizophrenia, schizoaffective disorder, bipolar disorder) * Subjects with other clinically diagnosed psychiatric disorders likely to affect the cognitive measures (as judged by a clinical advisor) * HIV positive * Past history or previous MRI evidence of brain damage, significant head trauma (including loss of consciousness as a result), brain surgery, stroke, or serious neurological disorders * History of alcohol or drug dependency in the last 2 years * Subjects with existing diagnosed gastrointestinal disorders likely to impact study results (as judged by a clinical advisor) * History of any major cardiovascular event, such as a myocardial infarction, stroke or TIA * Diagnosed COPD * Cancer, or cancer/treatment within the last 12 months * Diagnosis of type 1 or type 2 diabetes \< 3 months ago * Clinical diagnosis of liver or kidney disease * Diagnosed Epilepsy * Subjects with any other existing medical conditions likely to affect the study measures * BMI \>40kg/m2 * A habitual Mediterranean Diet Score (MDS) ≥9 * Habitual physical activity of \>60 minutes moderate activity per week, assessed using the International Physical Activity Questionnaire (IPAQ), short form * Currently actively engaged in a weight loss, other dietary, or physical activity intervention * Prescribed medications likely to influence the study measures (as judged by a clinical advisor) * Currently a participant or have participated in any other study involving an investigational product in the last 4 weeks * Metal implants, e.g. pacemaker that precludes MRI. * Claustrophobic which precludes MRI scanning.