How much fibre do you actually need a day?

We all know that fibre is good for us. We need it to keep our gut and bowel healthy, help lower cholesterol levels, stabilise blood sugar, and support our bodies in warding off disease and fighting infection.

It’s recommended that you eat around 30 grams of fibre a day, made up from around 30 different plant sources across the week.

Dr Holly Neill, Nutritionist and Science Manager at Yakult UK and Ireland, explains that gradually increasing your fibre intake towards the recommended level can significantly benefit your health - especially as most people in the UK fall well short of the target.

“The average adult is getting around 16-18 grams per day, versus the recommended 30 grams,” she says. “So for many people, the biggest ‘health boost’ comes from simply closing that gap rather than aiming extremely high.”

Dr Holly Neill

Fibremaxxing isn’t a term that takes much effort to understand. It’s about maximising your fibre intake to capitalise on the wide range of health benefits linked with eating more of it. While the message may seem well-intentioned on the surface, as with many social media trends, it often lacks the balance of credible health advice. In fact, fibremaxxing turns increasing fibre into a kind of challenge - packing as much of it into your meals as possible without a clear cut-off point or any real focus on the broader nutritional benefits of other food groups.

Many people who practice fibremaxxing don’t aim to stick to the 30-gram-a-day guideline. Instead, they push for intakes as high as 50 grams or more daily.

Neill explains that setting very high targets isn’t necessarily the best approach to increasing your fibre intake for health reasons - particularly when you consider your current diet and how well your gut can tolerate sudden changes of this kind.

She cautions that if you habitually consume low amounts of fibre and then dramatically increase your intake, it can lead to uncomfortable side effects.

These include:

• Bloating.

• Excessive gas.

• Constipation.

“As fibre increases stool bulk and fermentation by gut bacteria, without enough water alongside a gradual increase, this can overwhelm the gut,” she says. “Prolonged excessive fibre intakes may also interfere with the absorption of certain minerals such as iron, calcium, and zinc.”

Neill adds that, in general, this shouldn’t be a cause for concern, and emphasises that there are many factors at play in your body’s response to eating more fibre - including biological differences and the way food is prepared.

“Fibre intake is consistently associated with a reduced chance of developing cardiovascular disease, type 2 diabetes, and certain cancers,” she says. “There appears to be a plateau with health benefits associated with fibre once a high intake level is reached. However, with only 4% of the UK population consuming the recommended amount of fibre, for most it is advisable to focus on increasing their fibre - but not abruptly or to the extreme.”

Whatever your reasons for boosting your fibre intake, and however you choose to go about it, it’s helpful to be aware of the changes you might notice in your body and the timeline of effects - both positive and negative - that can come as you adjust.

Neill explains that when you eat more fibre, you’re effectively feeding your gut microbes, and over time, this supports the production of beneficial compounds such as short-chain fatty acids - including butyrate. Gut bacteria can begin to shift within a couple of days, but exactly how quickly you notice any changes can vary widely from person to person.

“What I can say is that some initial discomfort may happen if you increase fibre too quickly - things such as bloating, excess gas or even constipation,” she says. “That doesn’t necessarily mean something is ‘wrong’, but it is a sign you might need to slow down.”

To make the adjustment smoother, Neill recommends increasing your fibre intake gradually, making sure to drink enough fluids and include a wider variety of plant foods. Pay close attention to any effects such as bloating, excess gas, or constipation, and slow down if you need to, giving your gut time to adapt.

“Hydration also matters because fibre draws water into the gut during digestion,” she adds. “It’s also worth remembering that fibre isn’t just one thing. It comes in several forms, including soluble fibre, insoluble fibre, resistant starch, and prebiotic fibres.

“Because different gut microbes rely on different fibres, variety really matters, rather than trying to get all your fibre from one ‘hero’ ingredient."

Neill suggests you aim for a mix of fruits, vegetables, legumes, seeds, and whole grains - alongside adequate protein and healthy fats, so your overall diet stays balanced.

Blindly following an online health trend - even if it contains some elements that align with professional guidance - isn’t the best approach when trying to make genuine, lasting improvements to your lifestyle. As with any dietary change, adding more fibre to your meals requires sensible pacing, along with a healthy balance of hydration.

Neill recommends a ‘low and slow’ approach when increasing your fibre intake. Rather than making a sudden overnight change, she suggests adding a few extra grams each week and gradually building it up over time.

“Hydration is really important here,” she says. "If you increase fibre without enough fluid, you’re more likely to feel discomfort.”

When working out the right pace, Neill suggests monitoring your tolerance levels - for example, if you experience bloating, excess gas, or constipation, it may be a sign to slow the increase and build up more gradually.

“I also like the ‘little and often’ approach,” she adds. “Instead of trying to hit a huge amount of fibre in one sitting, spread it across the day with small additions - such as berries at breakfast, a handful of beans or lentils at lunch, and an extra portion of vegetables at dinner.

“Simple ways to add fibre without overdoing it include switching to whole grains, tossing beans into salads or soups, and sprinkling seeds over meals.”

Neill advises that when it comes to children, it’s important to remember they have much lower fibre requirements than adults. For example, toddlers and young children aged 2-5 need around 15 grams of fibre per day. Too much fibre at this stage can displace the energy-dense foods they need to support growth.

If you find you’re experiencing bloating and gas after increasing your fibre intake in a sensible way, your body could be simply adjusting to the change. Over time, this should decrease, but it can be helpful to keep a food diary to track both food and symptoms for a few weeks to see if there are common triggers.

Neill advises that if your symptoms are persistent, severe, or worsening - especially if you’ve already slowed down and kept your fluid intake up - you should take it as a sign to ease back and consider seeking personalised advice from a healthcare professional, particularly if you have a sensitive gut.

“People with inflammatory bowel disease (IBD) during active flares, irritable bowel syndrome (IBS), strictures or gastroparesis may find high-fibre diets make their symptoms worse," she says.

“In these clinical populations, fibre type, amount and timing require individualised management. Therefore, those struggling with IBS and other digestive conditions should speak with a healthcare professional - such as a specialist dietitian - to discuss their individual concerns.”

If you’re not getting the recommended amount of fibre in your diet and want to increase it, that’s a positive step towards better health. While fibremaxxing may sound less harmful than some other ‘maxxing’ trends, it’s still a more exaggerated approach than simply following established health guidelines, which exist for a reason.

Online hype isn’t the same as medical guidance, and an influencer isn’t a doctor. It’s best to rely on reputable sources for advice on improving your diet, rather than following fads that could do more harm than good.