A number of lifestyle factors have been recognised to play an important role in positively modifying medical and psychiatric diseases and their associated morbidity and mortality. These include, eating healthy food, greater physical activity, cessation of smoking, avoidance of alcohol and illicit substances. Additional lifestyle factors for healthy living include, safe and peaceful environment, optimal sleep, de-stressing and enjoyable activities, social connections/support and healthy mental activities. Physicians from the ancient times, through the middle ages to the early 20th century have recommended adoption of healthy lifestyle factors such as diet and exercise to manage medical and psychiatric disorders without really understanding their scientific basis. In this short paper, we discuss the important role lifestyle factors play in morbidity and mortality related to many important and common medical and psychiatric diseases. We explore how and if positively modifying lifestyle factors can help to improve and or prevent medical and psychiatric disorders with particular emphasis on food, diet and exercise.