The study investigates the impact of dietary changes on life expectancy (LE), particularly focusing on the transition from a typical Western diet (TW) to a more optimized diet (OD). This research builds on the framework presented by Johansson and colleagues, utilizing data from meta-analyses and mortality rates to quantify the potential health benefits. The objective is to assess the health outcomes associated with different food groups and provide a comprehensive evaluation of how dietary modifications can influence longevity. Methodology: The methodology involves a multi-step process to ensure robust and reliable results. Data collection was conducted using meta-analyses from PubMed to gather information on various food groups and their health impacts. Current mortality rates and causes of death were incorporated to estimate how changes in diet could affect life expectancy. The study compares the typical Western diet (TW), characterized by high intake of processed foods and sugars, with an optimized diet (OD) that emphasizes fruits, vegetables, nuts, legumes, and whole grains. An interactive R Package Shiny web application was developed to allow users to explore the estimated effects of dietary changes on LE, facilitating a dynamic analysis of the data. Results: The results reveal a significant potential increase in life expectancy when transitioning from a typical Western diet to a more optimized diet. The analysis shows that increased consumption of fruits, vegetables, nuts, legumes, and whole grains is associated with a reduction in mortality rates. Conversely, reductions in the intake of processed meat, red meat, and sugary beverages correspond with substantial health benefits. The optimized diet (OD) consistently demonstrates a clear positive impact on longevity compared to the typical Western diet (TW), underscoring the profound influence that dietary choices can have on health outcomes. Conclusion: The study concludes that adopting a more optimized diet can significantly enhance life expectancy. These findings highlight the critical role of dietary modifications as a strategic approach to improving public health. The research provides robust evidence to support the formulation of public health policies aimed at promoting healthier eating habits. By offering clear and actionable dietary recommendations, the study underscores the potential of diet as a powerful tool for enhancing longevity and reducing the burden of diet-related diseases. Impact of the research: The impact of this research extends across multiple domains. For public health, it offers evidence-based dietary recommendations that can be utilized by health organizations to improve population health. For policymakers, it provides a scientific foundation for developing dietary guidelines and policies designed to mitigate the prevalence of diet-related diseases. On an individual level, the study empowers people with knowledge to make informed dietary choices that can enhance their longevity and quality of life. Additionally, the research contributes to the academic community by adding new insights and methodologies to the existing body of literature on diet and health, paving the way for future studies in this field. Overall, this research underscores the transformative potential of dietary changes and provides a comprehensive, evidence-based framework for enhancing life expectancy through improved nutrition.