Metabolic & Cardiometabolic · Gut & Microbiome
Does fibre raise the appetite hormone GLP-1 soon after eating?
The claim, precisely: fiber-derived SCFA increases GLP-1
Modestly and inconsistently — fibre's gut by-products can nudge it up, but short-term human results often don't show it.
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
How the studies fall
What the evidence shows
The elegant SCFA->FFAR2/3->GLP-1/PYY satiety chain repeatedly fails to translate acutely in humans: inulin raised serum SCFA but did NOT raise GLP-1 or PYY. Mechanism != outcome — do not promise satiety-hormone effects.
The evidence (4)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Chambers ES, et al. (Frost) 2015 · Gut | RCT | supports | high | Colon-targeted inulin-propionate ester acutely raised postprandial GLP-1 and PYY and cut energy intake |
| Tolhurst 2012 · Diabetes | animal | supports | moderate | SCFAs trigger GLP-1 from L-cells via FFAR2; ffar2/3-null mice show blunted SCFA-evoked GLP-1 |
| Rahat-Rozenbloom S, et al. 2017 · Eur J Clin Nutr | RCT | tested-null | moderate | Inulin raised serum SCFA but did not increase GLP-1 or PYY (possible obesity SCFA-resistance) |
| Vanslette AM, et al. 2023 · Eur J Pharmacol | animal | tested-null | moderate | Sodium propionate did NOT rescue HFD-induced GLP-1 reduction (only 5-HT4 agonism did) |
Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.