Fibre is the least interesting thing on this website and it does more work than almost anything else on it.
The numbers
Women: 21–25 grams a day. Men: 30–38 grams a day.
Most people get about 15.
It varies from person to person, but that gap is close to universal — and it's a gap of roughly half.
Fifteen grams isn't a rounding error. It's the difference between a microbiome that can produce your satiety signals and one that can't, between a glucose curve that rises gently and one that spikes, and between a digestive system that runs and one that complains.
What you're actually feeding
Fibre isn't for you. You can't digest it — that's the definition. It passes through to your large intestine, where your gut bacteria ferment it and produce short-chain fatty acids.
Those short-chain fatty acids are what trigger GLP-1 and PYY, the hormones that tell your brain you've had enough. Which means the amount of fibre you eat today partly determines how hungry you feel tomorrow, through a mechanism that has nothing to do with willpower.
It also slows the rate at which sugar enters your bloodstream, which is why the same banana eaten whole and eaten as juice are two different metabolic events.
The smart way to get there
Her five, and they're the difference between this working and this being unpleasant.
Cook your vegetables — steam, roast or air fry. Cooking breaks down cell walls and does some of the digestive work in advance. Raw is not more virtuous; it's just harder.
Start slowly and drink lots of water. Fibre absorbs water. Adding a lot of fibre without adding water produces exactly the constipation you were trying to fix.
Pair it with healthy fats. Improves absorption of fat-soluble vitamins and slows things further in a good way — avocado with your lentils, olive oil on your roasted vegetables, tahini on anything.
Soak chia, oats and lentils. Overnight. It begins breaking down the compounds that make them hard work, and it's the reason chia pudding sits well when a spoonful of dry chia seeds doesn't.
Add cinnamon and ginger. Both support digestion, both cost nothing, both make the food better.
Six foods that do the heavy lifting
Lentils are the outlier here — a single cup gets you most of the way to a woman's daily target on its own. Raspberries are the surprise: eight grams a cup, which is more than most people expect from something that tastes like a dessert.
| Food | Roughly |
|---|---|
| Lentils, one cup cooked | ~15g |
| Raspberries, one cup | ~8g |
| Avocado, one medium | ~10g |
| Oats, half a cup dry | ~4g |
| Almonds, a handful | ~3.5g |
| Apple, with skin | ~4.5g |
Those are approximations, and the point isn't the arithmetic. It's that two of these in a day closes most of the gap, and nobody has to count anything.
A day that gets there without trying
- Breakfast — soaked oats with raspberries and chia
- Lunch — anything, plus a cup of lentils
- Snack — an apple, skin on, with almonds
- Dinner — roasted vegetables with olive oil, half an avocado
That's comfortably past target and it isn't a regime. Nothing has been removed.
Where people go wrong
- Jumping from 15g to 30g in a day. You'll be bloated and uncomfortable and you'll blame the fibre. Two to three weeks.
- Adding fibre without adding water. Fibre needs water to move. Without it you get the opposite of the intended result.
- Peeling everything. A large share of an apple's fibre is in the skin.
- Relying on a supplement. Different fibres feed different bacteria. A single-source powder is narrow where food is broad.
- Eating raw vegetables through a bloated week because they feel healthier. Cook them.
- Treating the number as a target to hit daily. Roughly there, most days, for years — that's what works.
The one thing
Soak oats and chia tonight. Add raspberries in the morning.
That's around 12 grams before you've properly woken up, and it's the single easiest structural change on this website.