Fiber is carbohydrate that human enzymes cannot break down, so it arrives in the large intestine essentially intact. What happens next depends on one physical property: does it dissolve in water? Soluble fiber dissolves and thickens; insoluble fiber does not and stays as particles. Walk both of them through the gut, then find out where that tidy two-bucket story starts to break down.
The journey begins
solubleinsoluble
Two fibers, one gutpress Next to follow them
Nine real fibers, placed by how much they thicken water and how readily colonic bacteria ferment them. Positions are schematic rankings drawn from published characterisations, not measured coordinates.
Daily energy intakesets the Adequate Intake targetkcal
Tap a food to add a serving; tap again for a second and third, then back to none. Gram splits are approximate — the soluble share of a food varies with cultivar, ripeness, processing, and the analytical method used.