Short-Chain Fatty Acids
You can't digest fiber. Your gut bacteria can, and they pay you in chemicals that run your colon and appetite.
Grounded in the research on short-chain fatty acids
What are they?
Tiny fatty acids with fewer than six carbons: mostly acetate (2 carbons), propionate (3) and butyrate (4). Your gut bacteria pump them out in roughly a 60:20:20 ratio when they ferment the fiber you can't break down yourself. Around 500 to 600 millimoles get made in your colon every day. They're the actual currency of the fiber-gut relationship, not the fiber itself.
Why not digest fiber myself?
You physically can't. Humans don't have the enzymes to break down most dietary fiber, so it slides through your small intestine untouched and lands in the cecum and large intestine. There, trillions of anaerobic bacteria ferment it. SCFAs are the byproduct of that fermentation. No fiber in, no fuel for the bugs, no SCFAs out. You're outsourcing the job to a microbe colony.