In this regard, obesity can dysregulate several peptides or their receptors that are known to decrease food intake, such as nesfatin-1, oxyntomodulin (OXM), CCK, glucagon-like peptide 1 (GLP-1), pancreatic polypeptide (PP), and PYY (44), as shown in Table 1. Here, PPY is linked to obesity due to melanocortin 4 receptor deficiency.