INS and fatty liver disease: Interestingly, RYGB-induced benefits on body weight relapsed shortly after onset of antibiotics and compromised metabolic health as demonstrated by reduced glucose clearance (Fig. 1f), compromised insulin sensitivity (Fig. 1g), elevated blood triglycerides (Fig. 1h) together with histological features of hepatic steatosis (Fig. 1i, j), and a systemically dominant pro-inflammatory cytokine profile (Fig. 1k) after 5 weeks of treatment.