PYY and obesity due to melanocortin 4 receptor deficiency: SCFAs were absorbed by the gut and release more gut hormones, such as glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), resulting in lower food intake (Freeland and Wolever, 2010; Lin et al., 2012), thereby curbing obesity (Keenan et al., 2015; Reiner et al., 2016; Namkoong et al., 2017).