Although four IRAK family members [IRAK1, 2, 3 (i.e., IRAK-M), and 4] are involved in TLR and IL-1R signaling pathways, IL-1R > IRAK1 signaling appears to be the most studied pathway, with sufficient evidence to support its central role linking the innate immune response to the pathogenesis of various diseases, including cancers, metabolic disorders, and non-infectious immune disorders. This evidence concerns the gene IRAK1 and metabolic disease.