Search words were "obesity," "fatty acids," "adipose tissue," "inflammatory markers," "macrophages," "immune cells," "leptin," "resistin," and "visfatin." The review yielded a total of 93 articles that emphasized the description of obesity as low-grade chronic inflammation or immune disease, its inflammatory markers, specifically resistin and visfatin, and the prevalence and effect of fatty acids on inflammation. Here, RETN is linked to obesity due to melanocortin 4 receptor deficiency.