When fiber is fermented by bacteria in the gut, acetate is produced as a waste product. It's absorbed and transported to the brain, where the acetate signal stops more eating.
An international team of researchers identified an anti-appetite molecule called acetate that is naturally released when we digest fiber in the gut. Once released, the acetate is transported to the brain where it produces a signal to tell us to stop eating.
Acetate is a short-chain fatty acid produced by bacteria in the gut.
I've also read that the short-chain fatty acids are anti-inflammatory.