INS and Obesity: In one trial that investigated the effects of SCFA acetate infusions in men living with overweight or obesity, distal colonic infusions gave the most significant improvement in metabolic markers.4 A follow-up trial showed a series of metabolic effects following rectal administration of SCFA mixtures, suggesting that potential exists for improving body weight control and insulin sensitivity.49 The SCFA mixtures used were in concentrations equivalent to those that could be realistically obtained following fiber consumption.