FFAR3 and obesity due to melanocortin 4 receptor deficiency: Sensing of SCFAs is an essential function for FFAR2 and FFAR3, and deficiency each of receptors result in chronic inflammation and obesity in mice (Ang et al., 2016; Kim, Kang, Park, Yanagisawa, & Kim, 2013; Yonezawa et al., 2013).