INS and obesity due to melanocortin 4 receptor deficiency: Although the relationship between the ratio of Firmicutes to Bacteroidetes and obesity has remained controversial (Collado, Isolauri, Laitinen, & Salminen, 2008; Koliada et al., 2017), one report showed that the ratio of Firmicutes to Bacteroidetes was higher in obese men than in obese women and was inversely correlated with peripheral insulin sensitivity in men, but not in women (Most et al., 2017).