The increased EPO levels found in severe obesity in our sample, their association with basal body weight, FM and FFM and their correlation with higher weight loss and changes in body composition in the short term after weight-loss therapies, suggest the role of EPO as a contributing factor in adipose tissue energy homeostasis as well as in the possible detection of patients who are more likely to respond initially to weight-loss therapies. This evidence concerns the gene EPO and obesity disorder.