Type 2 diabetes mellitus is one of the most common chronic health conditions around the world and is a major challenge to health care providers. Its incidence across the world is increasing. There is long-term affection of pancreas before symptoms start, allowing for a large window for early detection and prevention of the disease. We conducted this review using a comprehensive search of MEDLINE, PubMed, and EMBASE, January 1987, through March 2017. The following search terms were used: diabetes type 2, prevention diabetes type 2, effects of lifestyle on health, alcohol and diabetes, smoking and diabetes, preventive strategies for diabetes type 2. Our aim in this study is to understand the pathophysiology of diabetes mellitus type 2 with regards to the risk factors and how to prevent them. Diabetes mellitus type 2 is considered a preventable disease, therefore, studying its risk factors and trying to reduce them is very important. Even minor modifications in risk factors of the disease could achieve significant reduction in incidence and progression of diabetes. Weight loss, improved dietary intake, and increased exercise levels are the most important interventions that will lead to significant decrease in the occurrence of the disease.