Lifestyle factors such as diet and physical activity significantly influence cancer prevention, prognosis, and survivorship. This narrative review summarizes the impact of these factors on cancer development and clinical outcomes. It discusses the oncogenic mechanisms behind lifestyle factors, including how obesity, diet, and physical activity contribute to cancer risk. The review also highlights the role of lifestyle guidelines and dietary patterns in reducing cancer incidence, with a focus on breast and colorectal cancers. Studies show that adherence to lifestyle recommendations, such as a plant-based diet and regular physical activity, can reduce cancer risk. Physical activity has been linked to lower cancer incidence and improved survival rates, while obesity is associated with increased cancer risk and poorer outcomes. The review emphasizes the need for holistic approaches to lifestyle modifications, as the combined effects of multiple factors may be more significant than individual ones. The review also addresses the impact of lifestyle factors on cancer survivorship, noting that physical activity and healthy diets can improve quality of life and survival outcomes in cancer survivors. However, there is limited evidence on the long-term effects of lifestyle interventions on cancer recurrence and mortality. Future research should focus on identifying synergistic effects of lifestyle modifications and exploring their impact on various cancer subtypes beyond breast and colorectal cancers. In conclusion, lifestyle modifications, particularly diet and physical activity, play a critical role in cancer prevention and survivorship. While there is strong evidence supporting the benefits of these interventions, more research is needed to fully understand their impact and to develop effective, evidence-based strategies for cancer prevention and treatment.Lifestyle factors such as diet and physical activity significantly influence cancer prevention, prognosis, and survivorship. This narrative review summarizes the impact of these factors on cancer development and clinical outcomes. It discusses the oncogenic mechanisms behind lifestyle factors, including how obesity, diet, and physical activity contribute to cancer risk. The review also highlights the role of lifestyle guidelines and dietary patterns in reducing cancer incidence, with a focus on breast and colorectal cancers. Studies show that adherence to lifestyle recommendations, such as a plant-based diet and regular physical activity, can reduce cancer risk. Physical activity has been linked to lower cancer incidence and improved survival rates, while obesity is associated with increased cancer risk and poorer outcomes. The review emphasizes the need for holistic approaches to lifestyle modifications, as the combined effects of multiple factors may be more significant than individual ones. The review also addresses the impact of lifestyle factors on cancer survivorship, noting that physical activity and healthy diets can improve quality of life and survival outcomes in cancer survivors. However, there is limited evidence on the long-term effects of lifestyle interventions on cancer recurrence and mortality. Future research should focus on identifying synergistic effects of lifestyle modifications and exploring their impact on various cancer subtypes beyond breast and colorectal cancers. In conclusion, lifestyle modifications, particularly diet and physical activity, play a critical role in cancer prevention and survivorship. While there is strong evidence supporting the benefits of these interventions, more research is needed to fully understand their impact and to develop effective, evidence-based strategies for cancer prevention and treatment.