Similarly, dietary fiber intake can increase the production of SCFAs by gut microbiota, which subsequently stimulates GLP-1 secretion by acting on GPR41/FFAR3 and GPR43/FFAR2 on gut endocrine L cells, thereby improving obesity and IR (Samuel et al., 2008; Tolhurst et al., 2012; Nøhr et al., 2013). The gene discussed is FFAR3; the disease is obesity due to melanocortin 4 receptor deficiency.