Distal, not proximal, colonic acetate infusions promote fat oxidation and improve metabolic markers in overweight/obese men

, P=0.015), fasting peptide YY (PYY, P=0.01) and postprandial glucose and insulin concentrations (P<0.05), and tended to increase fasting plasma acetate (P=0.069) compared with placebo. Distal 100 mmol/l acetate administration tended to decrease fasting tumour necrosis factor-α (TNF-α; P=0.067) compared with placebo. In contrast, proximal colonic acetate infusions showed no effects on substrate metabolism, circulating hormones or inflammatory markers. In conclusion distal colonic acetate infusions affected whole-body substrate metabolism, with a pronounced increase in fasting fat oxidation and plasma PYY. Modulating colonic acetate may be a nutritional target to treat or prevent metabolic disorders.