How Much Fibre Do You Actually Need? (And Why Most of Us Are Falling Short)

If you had to guess how much fibre you eat in an average day, would you know? Most people don't, and it turns out most of us are eating a lot less than we think.

According to recent data pulled from the National Diet and Nutrition Survey, 96% of UK adults aren't hitting the recommended 30g of fibre a day. The average adult intake sits at around 16g, roughly half of what we actually need. No age group in the UK currently meets the target.

As a nutritional therapist, fibre is one of the first things I look at with almost every client, regardless of what's brought them to me. That's because it's not a niche nutrient with one narrow job. It affects digestion, blood sugar, cholesterol, hormones, weight management, and even mood and brain function.

Few single changes have this much reach.

Here's what fibre actually does, why so many of us fall short, and how to close the gap without overhauling your entire diet.

What Fibre Actually Does in the Body

Fibre is the part of plant food your body can't fully digest, but "can't digest" doesn't mean "doesn't matter." Quite the opposite.

It feeds your gut bacteria. Fibre is the main fuel source for the trillions of bacteria living in your gut. A well-fed, diverse microbiome is linked to better digestion, stronger immune function, and even mood regulation, since a large proportion of your serotonin is produced in the gut.

It supports healthy cholesterol levels. Soluble fibre in particular binds to cholesterol in the digestive tract and helps remove it from the body, which is why fibre intake is consistently linked to better cardiovascular health outcomes.

It keeps you fuller for longer. Fibre slows down digestion and the release of sugar into your bloodstream, which means steadier energy, fewer cravings, and a much easier time managing weight without needing to restrict.

It helps regulate hormones. Fibre plays a role in binding to and clearing excess oestrogen through the digestive system, rather than allowing it to be reabsorbed and recirculated. This is particularly relevant for anyone dealing with hormone-related symptoms.

It supports brain function. Emerging research continues to link fibre and gut health to cognitive function via the gut-brain axis, one of the reasons gut health has become such a focus in conversations about long-term brain health.

It supports cardiovascular health. Beyond just cholesterol, fibre has been consistently linked to lipid reduction, healthier body weight regulation, improved glucose metabolism, better blood pressure control, and reduced chronic inflammation. Fibre from wholegrains in particular has shown some of the strongest links to lower cardiovascular disease risk in research.

It supports immune function. Fibre has been linked to improved immune function through both microbiome-dependent and independent pathways, including increased resistance to infection. The short-chain fatty acids produced during fibre fermentation also appear to help regulate inflammatory markers in the body, meaning a well-fed microbiome may be doing more for your immune resilience than most people realise.

It supports steady energy levels. Because fibre slows the rate at which sugar enters your bloodstream, it helps prevent the sharp spikes and subsequent crashes that come from fast-digesting refined carbohydrates.

In short: whether you're focused on digestion, energy, weight, skin, hormones, or heart health, fibre is doing something for you.

Why So Many of Us Are Falling Short

If fibre does this much, why are 96% of us under-eating it? In my experience, it's rarely down to someone not trying. It comes down to how the modern UK diet is structured.

Ultra-processed foods dominate. A large proportion of what the average person eats day to day is ultra-processed, and these foods are typically stripped of fibre during manufacturing to extend shelf life and improve texture.

Low plant diversity. Most of us eat a fairly narrow rotation of the same handful of fruits, vegetables, and grains, week after week. Gut bacteria thrive on variety, not just volume, so even people eating "enough" plants can be missing out if they're always the same ones.

Refined carbohydrates are still the default. White bread, white rice, and white pasta remain the go-to choice for most people, largely because they're familiar, convenient, and often cheaper. Refining strips out much of the fibre-rich outer layer of the grain.

None of this is about willpower, it's about the food environment most of us are operating in.

What 30g of Fibre Actually Looks Like: how much fibre do you need

Thirty grams can sound like a lot until you see it broken down across a day:

• Porridge with berries, a spoon of chia seeds and some flaked almonds

• A salad with lentils and roasted vegetables, rocket, feta and olive oil

• A handful of walnuts or edamame as a snack

• Brown rice or quinoa in place of white rice at dinner

• A beef chilli loaded with kidney beans, topped with avocado, coriander and spring onion

None of this is "diet food." It's just food that happens to be doing a lot of quiet work in the background.

Signs You Might Not Be Getting Enough

A few patterns that can point toward low fibre intake, though they can have other causes too, so they're not diagnostic on their own:

• Bloating or irregular bowel movements

• Constipation

• Energy dips or blood sugar crashes a couple of hours after eating

• Feeling hungry again soon after a meal

• Skin that feels more reactive or breakout-prone than expected

• Hormones feel like they are all over the place

• Consistently craving something sweet after meals

• Frequently reaching for sugary or refined snacks mid-afternoon

If a few of these sound familiar, fibre is a reasonable place to start looking.

Simple Ways to Increase Your Fibre Intake

You don't need to overhaul your diet overnight, and you shouldn't. A sudden jump in fibre intake can cause the exact bloating and discomfort you're trying to avoid. Increase gradually, and drink enough water alongside it, since fibre needs fluid to do its job properly.

A few starting points:

• Swap one white carbohydrate a day for a wholegrain version: brown rice, wholemeal bread, or quinoa instead of couscous

• Add a tin of beans or lentils to a meal you already cook, like a bolognese or curry

• Leave the skin on potatoes

• Aim for two different plant foods at every meal, not just at dinner

• Build up slowly over several weeks, rather than all at once

  
  

The Bottom Line

Fibre isn't a wellness buzzword, it's one of the most well-evidenced, far-reaching nutrients in your diet, and one of the easiest to under-eat without realising it. Given that 96% of us are falling short, there's a good chance you are too, even if you already think of yourself as eating well.

The encouraging part is that fibre is genuinely one of the most fixable areas of nutrition. Small, consistent changes add up quickly, and you don't need to get everything right straight away.

If you'd like some support figuring out where the gaps are in your own diet, gut health or otherwise, book a free 20-minute call or find out more about working with me one-to-one.

Bella Dorey is a BANT-registered Nutritional Therapist (BSc, mBANT, CNHC) based in Bury St Edmunds, working with clients in-person and online across the UK. She specialises in gut, skin and hormonal health.