This systematic review investigates the effectiveness of lifestyle modifications in treating type 2 diabetes mellitus, particularly among smoking individuals aged 45-60. It highlights the increasing global prevalence of diabetes and the importance of lifestyle changes such as diet, exercise, and smoking cessation in managing the disease. The review analyzes the impact of smoking, diet, and physical activity on diabetes, emphasizing the need for weight management, healthy eating habits, and regular physical activity to control blood glucose levels and reduce the risks associated with type 2 diabetes. The study also underscores the importance of educating individuals about the benefits of lifestyle changes and the need for government initiatives to promote awareness and early diagnosis. Ultimately, the review concludes that adopting a healthy lifestyle can significantly reduce the risks associated with type 2 diabetes and improve overall health outcomes.