An area where the role of SCFA is gaining much interest is their effects in obesity and metabolic regulation (glucose and lipid homeostasis). Epidemiological and robust animal data demonstrates an inverse relationship between dietary fibre intake and adiposity and weight gain. Recent studies are beginning to provide insight into the role of SCFA. Acetate plays a role in central appetite regulation [
34], and increasing production in the distal colon may be more effective than the proximal colon, promoting fat oxidation, improved glucose homeostasis and inflammatory status [
35•]. The role of acetate in energy homeostasis and substrate metabolism has recently been reviewed elsewhere [
36]. Our recent work using an inulin propionate ester to target deliver to the large intestine has demonstrated in controlled human trials that propionate directly attenuates appetite and food intake [
37], influences food choice [
38], improves pancreatic function [
39] and modulates hepatic lipid accretion [
40]. Oral propionate has also been shown to increase fat oxidation in humans [
41]. Acute oral, but not intravenous, butyrate has been shown to reduce food intake and improve glucose and lipid profiles via a gut-brain neural circuit in animals [
42]. In overweight/obese men, colonic infusions of SCFA appear to increase fat oxidation, energy expenditure and PYY release, and decrease adipose tissue lipolysis [
43]. Inulin, a fructo-oligosaccharide prebiotic NDC which is readily fermented producing SCFA, has demonstrated beneficial effects on adiposity [
44] substrate metabolism [
45], insulin sensitivity [
46] and appetite regulation [
47‐
49] although the effects seen in humans are inconsistent and may be related to the levels of inulin intake [
50]. A recent meta-analysis tentatively concluded that inulin-type fructans elicit a beneficial effect on lipid profiles and glucose metabolism [
51].