Increased plasma FFA and total muscle ceramides (primarily C18:1, C20:0, C22:0, C24:1, C24:0) are observed in individuals with obesity and T2D, as well as impaired muscle FFA oxidation in obese premenopausal women and individuals with T2D [47,48,49] Furthermore, there is an inverse relation between visceral adiposity and insulin-stimulated FFA uptake [49]. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.