How much fibre do you need?
The NHS recommends 30g of fibre per day for adults. The American Heart Association recommends 25–30g. Despite these targets, surveys consistently show average intake is 17–20g/day in the UK and US.
Children need less: about 15–25g depending on age. Requirements do not change significantly between men and women at the same body size, though men tend to eat more food overall and therefore more fibre.
Daily fibre targets
Adults: 30g/day (NHS / AHA recommendation)
Average actual intake: ~18g/day (UK adults)
The gap: approximately 12g/day under target
Why fibre matters for health
Fibre is a carbohydrate that humans cannot digest. It passes largely intact to the colon, where it feeds beneficial gut bacteria (prebiotic effect) and adds bulk to stool. The health benefits are well documented across multiple domains:
- Gut health — high fibre intake is strongly associated with reduced colorectal cancer risk, improved bowel regularity, and a more diverse microbiome.
- Blood sugar — soluble fibre (oats, legumes, apples) slows glucose absorption, reducing post-meal blood sugar spikes and improving insulin sensitivity.
- Cholesterol — soluble fibre binds to bile acids in the gut, causing the liver to pull LDL cholesterol from the blood to produce more bile. Even 5–10g/day of soluble fibre can reduce LDL by ~5%.
- Weight management — fibre adds bulk without calories, increases satiety hormones, and slows gastric emptying — all of which reduce total calorie intake naturally.
- Cardiovascular disease — a 2019 Lancet meta-analysis found that each 8g/day increase in dietary fibre was associated with 5–27% reductions in coronary heart disease, stroke, and type 2 diabetes.
Highest-fibre foods by category
| Food | Serving | Fibre |
|---|---|---|
| Split peas (cooked) | 180g | 16g |
| Lentils (cooked) | 200g | 15g |
| Black beans (cooked) | 180g | 15g |
| Chickpeas (cooked) | 200g | 12g |
| Avocado | 1 medium (150g) | 10g |
| Oats (dry) | 80g | 8g |
| Edamame | 150g | 8g |
| Pear (with skin) | 1 medium | 5.5g |
| Broccoli (cooked) | 160g | 5g |
| Wholegrain bread | 2 slices (80g) | 4.5g |
| Almonds | 30g | 3.5g |
| Apple (with skin) | 1 medium | 4.4g |
How to increase fibre intake without digestive distress
Increasing fibre too quickly (especially from legumes) can cause bloating, gas, and discomfort. The solution is gradual increase — add ~5g more per week and drink plenty of water. Fibre absorbs water in the gut, and without adequate hydration, it can cause constipation rather than prevent it.
- Swap white bread, rice, and pasta for wholegrain versions (doubles fibre content).
- Add a serving of legumes (lentils, beans, chickpeas) to two meals per week, building up to daily.
- Eat fruit with the skin on (pear, apple, nectarine) rather than peeled.
- Add a tablespoon of flaxseeds or chia seeds to yoghurt or oats (5–7g fibre per tablespoon).
- Start lunch with a large salad containing mixed leaves, carrot, and cucumber.