Vrieze et al52 conducted a double-blind pilot RCT of nasoduodenally delivered FMT compared with autologous FMT for metabolic syndrome and reported a significant improvement in week 6 peripheral insulin sensitivity (p < .05) in favor of FMT, but not in hepatic insulin sensitivity (p = .08), diet composition, resting energy expenditure, or counter-regulatory hormones. This evidence concerns the gene INS and metabolic syndrome.