Dementia, is a critical global public health challenge with no effective pharmacological treatments. Recent research highlights the significant role of lifestyle interventions, particularly physical activity and dietary habits, in mitigating cognitive decline among the elderly and preventing the progression to dementia in individuals with Mild Cognitive Impairment (MCI). This comprehensive review explores the impact of physical exercise and dietary approaches on cognitive health, comparing strategies adopted in Western and Asian countries. Physical activity, including aerobic, resistance, balance training, and dual-task exercises, has been shown to enhance neurogenesis, improve cerebral blood flow, and delay cognitive decline. In Western countries, structured regimens such as the Mediterranean (MedDiet) and MIND diets are prominent, while Asian countries often integrate traditional mind-body practices like Tai Chi and culturally relevant diets rich in antioxidants and polyphenols. Although both regions recognize the importance of lifestyle changes in reducing dementia risk, their approaches differ significantly, shaped by cultural norms and dietary preferences. This review underscores the need for culturally tailored public health strategies to promote cognitive health globally, highlighting the importance of individualized approaches in MCI and dementia prevention.