A healthy diet is an indispensable fact for human health. Nowadays many diseases have become widespread for people because of unhealthy diets. An unhealthy diet contributes to lots of deaths each year in the U.S., due to nutrition related diseases such as heart disease, cancer, and type 2 diabetes.1 So what is healthy diet and can eating healthily prevent us from all diseases?Initially; in the past, there were diets such as Mediterranean diet, Traditional Asian diet, Scandinavian diet, which are associated with many civilizations.Even though all these diets have their own good aspects, experts say that a healthy diet means a’ balanced diet’. Having a balanced diet means choosing from all five main food groups, in the right quantities.Secondly, is there any healthy diet to prevent all diseases? A healthy diet can prevent lots of diseases but without physiological and psychological factors, only healthy eating is not enough. Warren Buffett, one of the world’s wealthiest investors, is eighty-four years old but he eats like a six years old child. He eats food such as chips and ice cream at breakfast. Buffett, also quarter of his diet is Cola, thinks that this is the most reliable way to eat.2 This diet, which is very dangerous for a person of eighty- four years under normal circumstances, has become a lifestyle for Buffett.Buffett’s story shows us the importance of psychological factors in diets.Finally, a healthy diet needs to be completed with sports to be effective in protecting from diseases.Studies have shown that a diet without sports can provide fat balance in the body, but the physiological equilibrium of other nutrients such as protein cannot be fully achieved.As it is understood from the first definition, diet is a part of a balance and it is not possible to achieve this balance without any physical activities.Consequently, a healthy diet can protect us from lots of diseases such as heart disease, cancer, and type 2 diabetes. Nevertheless, it should not be forgotten that a healthy diet should be accompanied with regular physical activities, and physiological and psychological situation of the person should be taken into consideration.Diet is an inevitable part of a balance and many factors work together to achieve this balance.