In recent years, the impact of dietary patterns on human health has come under an increasing attention. A wealth of data suggests that healthy dietary patterns reduce the risk of diet-related diseases. Japan currently has the longest average life span in both sexes in the world. Japanese diet has always been known to be healthy, and its unique dietary habits are one of the key reasons for the longevity of the Japanese people. This study examines the relationship between certain non-communicable diseases' incidence and mortality and the Japanese diet. According to this study, in women, eating a lot of soy products is related to a reduction of breast cancer risk. however, relations between soy foods and prostate cancer in men is still debatable. Consumption of soy and fish is linked to a reduction in cardiovascular disease. The high-sodium diet in Japan is related to the increase of stroke and gastric cancer risks, while green tea and coffee are related to a lower risk of stroke. There are few studies that analyses the association between dietary patterns and related diseases in Japan, and this study provides ideas for analyzing the relationship between diet and health in Japan.