Konjac Glucomannan Slows Gastric Emptying and Increases Satiety Hormones GLP-1 and PYY | Research

The takeaway

Higher-viscosity konjac glucomannan slowed gastric emptying, increased satiety hormones (GLP-1, PYY), and reduced appetite in a randomized controlled trial.

Higher viscosity = more GLP-1
Konjac glucomannan viscosity directly correlates with satiety hormone release and appetite suppression

What the researchers found

Higher viscosity konjac glucomannan delayed gastric emptying, increased GLP-1 and PYY secretion, and enhanced subjective satiety compared to lower viscosity or control conditions.

Why it matters

Konjac glucomannan is widely used as a dietary supplement for weight management. This study provides mechanistic evidence connecting its viscosity to specific appetite hormone responses and gastric motility effects.

The numbers in context

n=22; hunger p=0.006; fullness p<0.001; desire-to-eat p=0.002; prospective consumption p=0.001; 5 hormones measured (insulin, GLP-1, PYY3-36, CCK-8, ghrelin)

How the study worked

Combined in vitro gastric emptying simulation with a randomized controlled trial in humans. Measured rheological properties, gastric emptying, subjective appetite, glycemia, insulin, GLP-1, PYY, CCK, and ghrelin responses to different KGM viscosities.

Who was studied

22 healthy adults (11F/11M), mean age 23.2, mean BMI 20.6

What this study cannot tell us

Small sample size. Short-term acute testing — chronic effects unknown. In vitro gastric simulator may not fully replicate in vivo digestion. KGM palatability at high viscosity may limit practical intake.

How to read the evidence

Moderate — randomized controlled trial with mechanistic hormone data, but small sample and acute (single-meal) design.

When this study was published

Published in 2020; fiber-based appetite regulation continues to be studied alongside pharmaceutical GLP-1 approaches.

The bigger picture

This study connects the physical properties of a dietary fiber (viscosity) to specific gut hormone responses, bridging food science with the GLP-1 pathway that underpins modern weight loss drugs.

Questions still open

Would sustained konjac glucomannan intake produce clinically meaningful weight loss?
How does KGM-induced GLP-1 release compare quantitatively to GLP-1 drug therapy?
Could konjac be formulated to maximize viscosity in the stomach while being palatable?

Common questions

What is konjac glucomannan?

A highly viscous dietary fiber from the konjac plant root, commonly used in Asian cuisine and available as a weight loss supplement. It absorbs water and forms a gel in the stomach, which this study shows triggers satiety hormone release.

How does konjac fiber relate to GLP-1 drugs like Ozempic?

Both stimulate GLP-1 release, but through different mechanisms. Konjac triggers GLP-1 naturally by slowing digestion and stimulating gut cells, while drugs like semaglutide directly activate GLP-1 receptors. The fiber effect is much milder than pharmaceutical GLP-1.

Read the original research

In vitro gastric emptying characteristics of konjac glucomannan with different viscosity and its effects on appetite regulation.

Food & function, 11(9), 7596-7610

View on PubMed ↗Publisher’s paper ↗

Citation

Shang, Longchen; Wang, Yi; Ren, Yanyan; Ai, Tingyang; Zhou, Peiyuan; Hu, Ling; Wang, Ling; Li, Jing; Li, Bin. (2020). In vitro gastric emptying characteristics of konjac glucomannan with different viscosity and its effects on appetite regulation.. Food & function, 11(9), 7596-7610. https://doi.org/10.1039/d0fo01104e