Chronic systemic inflammation plays an important role in the development of metabolic diseases such as cardiovascular metabolic diseases, diabetes, non⁃alcoholic fatty liver disease, and cancer. Diet is an important factor that regulates body′s inflammatory status. In recent years, a literature⁃derived, population⁃based dietary inflammatory index (DII) was developed to provide a tool that could be used to assess the inflammatory potential of an individual′s diet. A large body of research has thus recently emerged about the associations between the DII and the risk of metabolic diseases. The DII was based on the literature on dietary composition and inflammation published between 1950 and 2014. Articles were scored according to their effects on six inflammatory biomarkers: IL⁃1β, IL⁃4, IL⁃6, IL⁃10, TNF⁃α and C⁃reactive protein. According to a composite global database of foods and nutrients consumption from 11 representative countries on four continents, individuals′ intakes to be expressed relative to the range of intakes of the forty⁃five food parameters, then the final DII score were calculated. In this review, we summarize the development and scoring of the DII, as well as recent advances in understanding the relationship between the DII and metabolic diseases such as cardiovascular metabolic diseases, diabetes, and cancer.