Not all fibre works the same way — here's the difference, and why it matters less than you'd think day to day.
"Fibre" is really an umbrella term for several distinct compounds with different effects — lumping them together as one number misses meaningful differences.
Dissolves in water, forming a gel that slows digestion and helps stabilise blood sugar. Found in oats, beans, apples and citrus.
Doesn't dissolve, adding bulk that supports regular digestion. Found in whole grains, nuts and vegetable skins.
A specific subset that's fermented by gut bacteria into short-chain fatty acids linked to reduced inflammation. Found in garlic, onions, leeks and legumes.
Starch that resists digestion and acts similarly to fibre — found in cooled cooked potatoes and rice, green bananas, and legumes.
Most whole plant foods naturally contain a mix of these types together, which is part of why THE FAD's Food signal rewards overall fibre and plant diversity rather than requiring you to track each type separately — the practical advice (more whole plants, more variety) captures most of the benefit regardless.