How much fibre do you need a day?
The UK figure for adults is 30g. Most of us are about 10g short, and the gap closes with fewer changes than you might expect.
An adult in the UK should aim for 30g of fibre a day. That is the government guideline set out by the NHS, which also says most adults currently manage about 20g. Children need less, and the amount rises with age: about 15g at 2 to 5, 20g at 5 to 11 and 25g at 11 to 16.
Thirty grams can sound like a lot of something you cannot see. It helps to think of it as a pattern across the day, since no single food or meal is going to carry the whole amount.
How far short are we?
The published figures differ a little. The NHS says about 20g for adults. The British Dietetic Association gives an average of about 18g, or roughly 60% of the target. The British Heart Foundation quotes about 16g. Different sources draw on different surveys and dates, so we would not read much into the spread. All of them point the same way: the typical adult is eating well under the guideline, by somewhere between a third and a half.
Teenagers have further to go. The NHS puts the average for 11 to 18 year olds at 16g a day, against about 25g for most of that age group.
Why the number is worth bothering with
The NHS links eating plenty of fibre with a lower risk of heart disease, stroke, type 2 diabetes and bowel cancer. It also helps digestion and helps prevent constipation. That wording matters. "Associated with a lower risk" describes a pattern seen across diets over time. It does not promise that a particular bowl of something will protect a particular person.
There is a more immediate reason too. The NHS notes that higher fibre starchy foods can help you feel full for longer, which many people notice well before they notice anything else.
A day that reaches 30g
This is the NHS's own worked example, and it is ordinary food. The page stresses that the figures are approximate, because fibre depends on how a food is made and how much of it you eat.
| Meal | What is on the plate | Fibre |
|---|---|---|
| Breakfast | 2 slices of wholemeal toast with peanut butter, a medium orange | 8.3g |
| Lunch | Wholemeal spaghetti with lentil and tomato sauce | 11g |
| Dinner | Grilled chicken breast, skin-on baked potato, carrots and green beans | 11.2g |
| Total before snacks | 30.5g | |
Notice what is doing the work. The potato keeps its skin. The pasta is wholemeal. The sauce has lentils in it. None of these is a special product, and the meals are recognisably what plenty of households already cook, with one or two ingredients changed.
Breakfast is often the easiest place to start, because it is the meal people tend to repeat. The NHS suggests porridge, plain wholewheat biscuits or plain shredded whole grain. A 40g serving of oats gives about 3.1g, according to the British Heart Foundation, so porridge on its own does not get you far, but fruit and nuts on top raise it. We go through the rest of the bowl in our piece on whether porridge is healthy.
Foods that pull their weight
The BDA publishes a table of fibre content. A few figures per 100g show where the density is:
- Shredded wholewheat or bran cereals: 13g to 24.5g
- Almonds: 7.4g, peanuts: 7.6g
- Boiled peas: 5.6g
- Baked beans in tomato sauce: 4.9g
- Boiled wholemeal spaghetti: 4.2g
- Strawberries: 3.8g
- Boiled broccoli: 2.8g
You would not eat 100g of almonds in a sitting, so treat these as a comparison between foods and not as portions. The NHS also recommends variety over a lot of one thing, and that is a sound instinct: different plant foods contain different types of fibre. The BDA separates soluble fibre, found in fruit and oats, from insoluble fibre, found in wheat bran and nuts.
Reading fibre on the pack
Most pre-packaged foods carry a nutrition label, though fibre is not always listed. Two thresholds are useful. A food with 6g or more per 100g can be described as high fibre, and one with 3g or more per 100g as a source of fibre. Compare per 100g and not per serving, because serving sizes are set by the manufacturer. Our guide to choosing a breakfast cereal runs through the other numbers on the same panel, and this one on bread labels covers the wording on the front.
Go up slowly, and drink more
If you are currently well below 30g, do not try to fix it by Thursday. The BDA advises raising fibre gradually, because a sudden jump can cause bloating and wind while your gut adjusts. It also advises drinking plenty of fluid, since fibre draws water into the bowel. The Eatwell Guide figure for fluids in general is 6 to 8 cups or glasses a day.
A workable approach is to change one meal at a time and leave it a week or two before changing the next.
When more fibre is not the right move
The 30g figure is for general health, and the BDA says advice may need adjusting for medical history and tolerance. People with conditions such as irritable bowel syndrome can find that larger amounts of fermentable fibre bring on bloating, wind or diarrhoea. If that sounds familiar, or you have a bowel condition, a GP or registered dietitian can tailor the advice. Please also see a GP about any change in your bowel habits that lasts or worries you, and do not try to manage it with diet alone.
Dried fruit deserves a small footnote. It counts towards fibre, but the NHS points out that it is sticky and can raise the risk of tooth decay, so it is better eaten with a meal than as a snack between meals.
This article is general information and is not medical advice. Guidance changes, so check the linked sources for the current figures. Last reviewed 17 June 2026.