Am I eating enough fibre each day?

If you’ve seen people talking about “fibremaxxing” online, you might be wondering whether you should be eating a lot more fibre too.

The advice usually sounds simple enough: add more oats, beans, lentils, chia seeds, vegetables, fruit, wholegrains, nuts and seeds. And to be fair, fibre does deserve the attention. Most adults in the UK do not eat enough of it, and getting more fibre can support your digestion, bowel habits, cholesterol, blood sugar and long-term gut health.

The problem is that your gut may not thank you if you go from very little fibre to several high-fibre meals overnight.

A sudden change can leave you feeling bloated, windy, crampy or uncomfortably full, especially if you have a sensitive gut or IBS. I see this quite often in clinic. Someone tries to eat “properly”, adds lots of beans, lentils, bran or seeds at once, then feels worse and assumes fibre does not suit them.

Usually, fibre itself is not the issue. The speed of the change is.

Your digestive system and gut bacteria need time to adapt. Rather than aiming for as much fibre as possible, the aim is to find a steady amount and variety of fibre that supports your gut without making every meal feel like hard work.

Why do we need fibre?

Fibre is the part of plant foods that the small intestine does not fully digest. Instead, it travels into the large bowel, where it plays several important roles.

Some types of fibre help to soften stools and make them easier to pass. Others provide food for the trillions of bacteria living in your gut. As these bacteria ferment certain fibres, they produce beneficial compounds that help support the health of your bowel.

Fibre can also:

• Help support regular bowel movements
• Keep you feeling fuller for longer
• Support healthy cholesterol levels
• Help with blood sugar control
• Contribute to long-term heart and bowel health

So although people often associate fibre with constipation, its benefits go well beyond simply helping you go to the toilet.

Current UK recommendations suggest adults aim for around 30g of fibre each day, but most people eat considerably less than this.

What are the signs I might not be eating enough fibre?

Constipation is often the first thing people think about. Stools may become hard, dry, difficult to pass or less frequent than usual.

You may also notice that you’re hungry again soon after eating, particularly if your meals contain very little fruit, vegetables, wholegrains, beans or pulses. Fibre slows digestion and adds bulk to meals, helping you stay fuller for longer.

Eating very little fibre may also reduce the variety of food available for your gut bacteria. Like us, different gut bacteria enjoy different foods, which is one reason why eating a wide range of plant foods appears to support a healthier gut microbiome.

However, it’s important to remember that a lack of fibre does not always cause constipation, bloating or abdominal pain.

IBS, coeliac disease, thyroid problems, medication, stress, reduced physical activity, inadequate fluid intake and a range of other digestive conditions can all produce very similar symptoms.

If your symptoms are persistent, worsening or new, it’s worth getting them assessed rather than assuming you simply need to eat more fibre.

Can eating more fibre make bloating worse?

Yes, especially if you increase it too quickly.

When fibre reaches your large bowel, your gut bacteria begin breaking some of it down. This is completely normal and one of the reasons fibre is so beneficial. However, this process also produces gas.

If your gut isn’t used to larger amounts of fibre, that extra gas can leave you feeling bloated, uncomfortable or windy.

Foods that commonly cause symptoms when people increase them too quickly include:

• Beans
• Lentils
• Chickpeas
• Bran cereals
• Large portions of vegetables
• Fibre supplements
• Large amounts of chia or flaxseeds
• Some high-fibre snack bars or powders

This doesn’t mean these foods are “bad” for your gut. More often, it simply means your gut needs longer to adjust or that a smaller portion would suit you better.

If you have IBS or a particularly sensitive digestive system, this gradual approach becomes even more important. A food can be incredibly nutritious but still trigger symptoms if you introduce it too quickly or eat it in large quantities.

Can you eat too much fibre?

Although most people would benefit from eating more fibre, you can have too much.

Very high fibre intakes, particularly when you increase them suddenly, can cause bloating, wind, abdominal cramps, constipation or loose stools.

Regularly eating well above around 50g of fibre each day may also reduce the absorption of some minerals, such as iron and zinc, particularly if your overall diet isn’t well balanced.

This isn’t a reason to avoid healthy foods like fruit, vegetables, oats or beans. It simply reminds us that more isn’t always better.

Some people also need to be more cautious with very high fibre diets. Young children, frail older adults and people who struggle to maintain their weight may find very high-fibre meals too filling, making it harder to meet their energy and protein needs.

Like most things in nutrition, balance is usually more important than extremes.

Which foods are good sources of fibre?

Fibre comes naturally from plant foods, and different plants provide different types of fibre. That’s one reason why variety matters just as much as the total number of grams.

Good sources include:

• Wholegrain bread, oats, brown rice and wholewheat pasta
• Beans, lentils, chickpeas and peas
• Fruit, particularly apples, pears, berries, oranges and dried fruit
• Vegetables such as carrots, broccoli, peas, sweetcorn and leafy greens
• Potatoes with their skin on
• Nuts and seeds, including almonds, pumpkin seeds, chia seeds and flaxseeds

If your digestion is particularly sensitive, you don’t have to start with the foods highest in fibre.

Many people find they tolerate foods such as oats, kiwi fruit, berries, carrots, potatoes with the skin on, lentil soup or small amounts of ground flaxseed more comfortably than very large portions of beans, bran cereals or raw cruciferous vegetables.

The important thing isn’t to eat every high-fibre food at once. Instead, focus on gradually increasing the range of plant foods you enjoy.

Does the type of fibre matter?

Absolutely. Fibre isn’t one single nutrient. Different plant foods contain different types of fibre, and they behave differently inside the gut.

Some fibres help stools hold onto water, making them softer and easier to pass. Others add bulk to stools. Some are readily fermented by gut bacteria, while others pass through the digestive system relatively unchanged.

This is why two people eating exactly the same amount of fibre can have very different experiences.

It’s also why I’m generally more interested in the overall variety of plant foods someone eats than whether they’ve managed to hit a particular fibre target.

Rather than relying on one “superfood” or one high-fibre cereal, aim to include a wide range of fruits, vegetables, wholegrains, beans, lentils, nuts, seeds, herbs and spices across the week.

Your gut bacteria thrive on variety.

Are fibre supplements worth taking?

For some people, yes.

Supplements such as psyllium husk can help certain bowel symptoms, particularly constipation, but introduce them gradually and take them with enough fluid.

High-fibre cereals, snack bars and powders can also have a place, but it’s worth looking beyond the headline fibre claim.

Some products contain large amounts of added sugar, sugar alcohols or sweeteners that may worsen bloating or diarrhoea, particularly if you have IBS.

As with most nutrition advice, context matters more than marketing.

How can I increase fibre without upsetting my gut?

The biggest mistake I see is trying to change everything overnight.

Instead, choose one small change and give your gut several days to adapt before making another.

For example, you could:

• Swap white bread for wholegrain bread
• Add oats to your breakfast
• Include an extra portion of fruit each day
• Add a small serving of beans or lentils to a meal
• Increase your vegetable intake gradually
• Sprinkle a small amount of ground flaxseed or chia seeds onto porridge or yoghurt

It also helps to spread your fibre intake across the day rather than eating one very high-fibre meal.

Don’t forget about fluid either. Fibre works best when you’re drinking enough, particularly if you’re increasing wholegrains, seeds or fibre supplements.

If beans or lentils tend to make you windy, try starting with small portions, rinse tinned varieties well and increase them gradually. Soups and stews are often better tolerated than large, dry portions.

Remember, you’re not trying to reach a target as quickly as possible. You’re giving your gut time to adapt.

When should I be more careful with fibre?

For most people, fibre is incredibly beneficial.

However, it’s sensible to seek personalised advice before making major dietary changes if you have:

• IBS
• Inflammatory bowel disease
• Diverticular disease
• A bowel narrowing, or stricture
• Swallowing difficulties
• A history of bowel obstruction
• Been advised to follow a low-fibre or low-residue diet

Someone with constipation-predominant IBS may benefit from a very different approach to someone with diarrhoea-predominant IBS.

The type of fibre often matters just as much as the amount.

When should bloating or constipation be checked?

Occasional bloating or constipation is common, particularly after changing your diet.

However, if symptoms persist for several weeks, continue returning, become painful or begin affecting your appetite, sleep or quality of life, it’s worth speaking to your GP or another healthcare professional.

You should seek medical advice promptly if you notice:

• Blood in your stool
• Black stools
• Unexplained weight loss
• Persistent vomiting
• Difficulty swallowing
• Severe abdominal pain
• A swollen or hard abdomen
• Fever
• Anaemia
• A new abdominal lump
• Symptoms that regularly wake you from sleep

A healthcare professional should also assess new and persistent bloating later in life, particularly if there’s a family history of bowel cancer, ovarian cancer, inflammatory bowel disease or coeliac disease.

Although fibre can help many digestive symptoms, it shouldn’t explain away symptoms that are new, persistent or concerning.

Finding the right fibre balance for your gut

For most people, eating more fibre is one of the best things you can do for your long-term gut health.

But more isn’t always better.

Start where you are. Make one small change at a time. Focus on eating a wider variety of plant foods rather than chasing the highest possible fibre intake.

Those gradual, sustainable changes are far more likely to improve your digestion than trying to transform your diet overnight. And if increasing fibre consistently makes your symptoms worse, don’t assume you simply need to push through. It may be a sign that you need a more personalised approach.

Every gut is different, and finding what works for your body is always more important than following the latest nutrition trend.

About the author

Katie Sanders is an accredited Dietitian and Nutritionist with experience across NHS and private practice settings. She specialises in irritable bowel syndrome (IBS), gut disorders and nutrition support, and currently practises at BMI Blackheath Hospital, BMI Sloane Hospital and BMI Chelsfield Park Hospital. Katie provides evidence-based, personalised dietary advice for a wide range of concerns, including allergies, coeliac disease, diabetes, cardiovascular disease and weight management. With specialist training in the low FODMAP diet, she is known for her empathetic, practical approach, helping patients make meaningful changes that fit their lifestyle, health goals and food preferences.