We hypothesised that supplementing the diet of adults with overweight and obesity with 20 g IPE for 42 days would improve insulin sensitivity compared with both a high-fermentable (inulin) and low-fermentable (cellulose) fibre control through modulatory effects on gut bacterial composition, reductions in NEFA levels and improvements in inflammatory markers. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.