We need to talk about fibre. It plays a key role in a varied, balanced diet, yet only 4% of UK adults are hitting their recommended daily intake of 30g. On average, we’re getting just 14g per day – and it matters. Fibre isn’t just about keeping things moving, it’s foundational to long-term health.
To dig deeper into why fibre deserves more love, we went along to ZOE’s Fibre Fest – a gathering of leading scientists and nutritionists exploring the latest research on gut health. The message was unanimous: fibre is the addition your diet deserves.
What is fibre?
Fibre is a complex carbohydrate found in whole plants. But unlike other carbs (like sugars and starches), we can’t digest it. That’s why our clever gut microbiota are so important – they digest fibre for us. We consume two different types of fibre:
Insoluble fibre
You’ll mostly find insoluble fibre in wholegrains – think brown rice, quinoa and buckwheat – and wholewheat foods. But also in beans, cauliflower, broccoli, carrots, potato skins, celery, courgette, leafy greens, dried fruit, nuts and seeds. Upping insoluble fibre intake can help to relieve constipation.
Soluble fibre
Oats and barley are great sources of soluble fibre. You’ll also find it in pulses, beans and sweet potatoes, as well as peas, apples, oranges and avocados. Chia seeds and berries packed with tiny seeds – raspberries and blackberries – are also brilliant sources. It slows our digestion, can help lower blood cholesterol, stabilise blood sugar and support gut health.
Both types matter. And most importantly, different plants contain different fibres – variety is key when it comes to a healthy diet.
Beyond the traditional labels
We often talk about fibre as if it’s one thing. In reality, it’s a large family of plant compounds that behave very differently in the body. The traditional labels – soluble and insoluble – are still useful, but they’re increasingly recognised as too simplistic. Many fibres don’t fit neatly into one category, and their behaviour can change depending on their food source and processing.
A more helpful way to understand fibre today is by looking at what it does in the gut:
- How fermentable it is – how much gut bacteria can break it down
- Whether it is viscous – does it form a gel when mixed with fluid?
These characteristics help explain why fibre-rich diets are associated with different health benefits.
Why is fibre important?
Fibre keeps us regular by bulking out stool and giving gut muscles something to work with. It also binds to cholesterol in the gut, helping to remove it from the body. As Professor Sarah Berry (Chief Scientist at ZOE) explains: “10–15% of bad cholesterol can be reduced by a bowl of porridge in the morning.”
Fibre also feeds your gut microbiome. When your microbes ferment fibre, they produce short-chain fatty acids – powerful compounds that nourish your gut lining and influence immunity, hormones, metabolism, heart health and even brain function.
As Dr Federica Amati puts it, some of our trillions of gut microbes “are quite picky”. Some bugs will only eat certain fibres (there’s one bug that will only eat coffee, for example). Your gut microbiome is resilient, but what you eat changes its composition. It’s an ecosystem and diversity keeps it thriving.
There is strong evidence that fibre-rich diets (particularly those high in wholegrains, fruits and vegetables) are associated with lower risk of cardiovascular disease, type 2 diabetes and colorectal cancer. Fibre also plays a well-established role in digestive health, helping prevent constipation when consumed alongside adequate fluid.
Nutritionist Rhiannon Lambert highlights emerging research suggesting fibre can help bind to toxins, with early evidence pointing to a role in reducing microplastics in the body. As she says, “the missing part of your diet is right in front of you […] and you can eat it on a budget.”
30 is the magic number
‘The Fibre Formula’ as described by Rhiannon Lambert in her book recommends:
- 30g of fibre per day (although some global populations consume up to 90g daily!)
- 30 different plants per week.
Why 30 plants? Because different plants contain different fibres and polyphenols, feeding different microbes. As Dr Federica Amati explains, hitting 30+ plants a week is “going to give your microbes as much of the good stuff” as possible.
And here’s another 30 to remember: chew each mouthful around 30 times. Chewing properly slows eating, supports digestion and helps regulate appetite by allowing your gut-brain signals time to register fullness.
Boosting fibre, done right
Hitting 30g per day doesn’t have to be complicated. Small additions across the day make a big difference:
- A bowl of porridge topped with nuts, seeds and berries can provide 8-10g of fibre
- An apple with a handful of nuts adds another boost
- Lentils or beans in a main meal can deliver 6-8g of fibre
- Add chia seeds, leafy greens or wholegrains like barley or spelt to round things out
According to the Fibre Fest panel, one of the biggest cultural shifts we need is rethinking how we build meals. Too often, we design plates around animal protein. Instead, try building around plants first, with meat or fish as a side, not the centrepiece. Adopting a flexitarian diet is a great place to start.
‘Fibremaxxing’ vs ‘fibrelayering’
If you’re currently eating around 14g per day, jumping straight to 35g overnight isn’t wise. As nutritionist Rob Hobson reminds us, the gut plays a key role in immunity and energy regulation, but your microbes need time to adapt. Increase fibre slowly, build it up methodically and drink plenty of water. You can also try soaking pulses and legumes overnight to make them easier to digest.
Avoid “fibremaxxing”, which refers to loading up on powders, bars or a fibre-packed food in one hit. It can feel intense, uncomfortable and unsustainable. Instead, try fibrelayering: spreading different fibre sources across meals and throughout the week. In turn, you’ll enjoy more variety and better balance. Plus it’s easier to stick to.
The truth about fibre supplements
Fibre supplements can have a role, but as Professor Sarah Berry points out, they lack the full package. When you eat whole plant foods, you’re not just getting fibre, you’re getting bioactives like polyphenols and the structural integrity of the plant cell wall. In a ZOE study comparing whole almonds to ground almonds, participants absorbed around 30% fewer calories when the fibre structure remained intact. The physical matrix of whole foods changes how we digest and absorb nutrients.
The key takeaway
Here in the UK, only 7% of adults know that 30g of fibre is the target to aim for.
While protein dominates headlines and supermarket shelves, most of us are easily hitting the recommended protein target. Fibre is the quiet overachiever we’ve been overlooking – it may be the addition your diet needs. Think 30g per day, 30 plants a week, and 30 chews per bite.
Want to learn more? Discover the secret to winter wellness.