Owing to good flavor and taste, high-fat diet (HFD) has been well accepted and favored by an increasing number of people. However, long-term HFD consumption may contribute to the pathogenesis of three kinds of common metabolic diseases, including obesity, hyperglycemia and cardiovascular diseases. These HFD-induced metabolic diseases not only reduce individual life quality, but also increase social medical burdens. Of note, maternal HFD also significantly increases the risk for obesity, hyperglycemia and cardiovascular diseases. Therefore, the harmful effects of HFD should be received enough attention. Recently, experimental findings have suggested that HFD-induced inflammation disrupts lipid and energy metabolism, promotes the development of insulin resistance and mediates the formation of atherosclerotic plaque and thrombus, highlighting the critical roles of inflammation in the pathogenesis of metabolic disorders. Apart from inflammation, many other factors also cause these metabolic diseases. In this article, the current knowledge on how HFD triggers inflammation, obesity, hyperglycemia and cardiovascular diseases is comprehensively discussed. This review provides new ideas for the alleviation of metabolic diseases and the development of functional foods.