More than nine in 10 Britons are failing to consume enough fibre, a dietary shortfall that experts say is putting the nation’s digestive health at risk and fuelling a rise in serious conditions including bowel cancer.
Official figures show that adults aged 19 to 64 typically consume only around 19g of fibre per day, while those over 65 average just 17.5g — far below the recommended 30g. A 2023 report found that 96% of people aged 11 and older do not meet the target. Only about 9% of UK adults achieve the recommended intake, meaning the population would need to increase its fibre consumption by at least a third to reach healthy levels.
The consequences of this deficit are significant. Research indicates that adding just 7g of fibre to the daily diet — roughly equivalent to a serving of beans or two slices of wholemeal bread — can reduce the risk of colon cancer by 8%, cardiovascular disease and heart attacks by 9%, strokes by 7%, and Type 2 diabetes by 6%. “We know there is a strong association between how much fibre you have and a lower risk of getting colon cancer,” said Dr Wendi LeBrett, a California-based gastroenterologist. “It feeds your gut microbiome, and that plays a role in your mood, skin and many other factors around your body.”
Fibre also promotes the growth of beneficial gut bacteria such as Lactobacillus and Bifidobacteria, which support digestion and overall health. The accepted recommendation is 25–35g of fibre per day depending on body size, LeBrett said, noting that “an apple has about 4g of fibre. Then for lunch or dinner, a serving of beans can get you 5–6g of fibre.”
Building a fibre-rich diet
The starting point for good gastric health is a diet high in fibre, fruit, vegetables, legumes and wholegrains, said Dr Nisha Patel, a consultant gastroenterologist and interventional endoscopist at Imperial College Healthcare NHS Trust in London. She also advised avoiding irritants including “alcohol, caffeine, fatty or spicy foods and artificial sweeteners,” and warned that “large, late meals can also trigger gastrointestinal symptoms.”
Increasing fibre intake can be achieved by incorporating more fruits, vegetables, wholegrains such as wholemeal pasta, brown rice and oats, legumes including beans, lentils and chickpeas, as well as nuts and seeds. Aiming for five portions of fruit and vegetables daily remains a core recommendation. Dr Ajay Verma, a consultant gastroenterologist at Kettering General Hospital in Northamptonshire, highlighted specific foods that aid digestion: “Kiwi is one of the most effective dietary interventions for constipation. We also recommend linseeds or flax seeds, because these are low-cost, natural laxatives that are very well tolerated. Stir them into yoghurt with some fruit.”
For those prioritising protein intake, Verma urged caution. “You may be having more protein in your diet to help with muscle building and the way your body functions, but that may mean you reduce how much fibre you have,” he said, stressing the need to consciously add fibre where necessary.
Fibre supplements such as psyllium husk or inulin are available, but experts generally recommend obtaining fibre from whole foods. Anyone considering supplements should consult a healthcare professional. “Some people need to take a fibre supplement to reach that goal,” LeBrett acknowledged.
Hydration is critical when increasing fibre consumption. Water softens the stool and supports smooth movement through the colon, preventing constipation and bloating. Patel recommended 1.5–2 litres of fluid daily — a figure that includes coffee, fruit, soups and other foods. UK government advice suggests aiming for 6–8 glasses (1.2 to 1.5 litres) of fluid per day, though individual needs vary based on climate, activity levels and diet. Caffeinated drinks contribute to fluid intake but their diuretic effect should be considered; fruit juice and smoothies should be limited to one small glass (150ml) per day due to their high sugar content.
Excess wind is another common complaint that fibre can address. “Wind to a degree is a normal phenomenon as we digest our food,” said Verma. “If you have a lot of wind, it is probably because you’ve got stuff sat in your bowels for longer than it needs to be. Increase the amount of fibre in your diet to clear your bowels as much as possible.”
The Mediterranean diet has been shown to lead to better digestive health. “Eat plenty of fruit, vegetables and fish, and try to reduce or have a low intake of processed foods, high dairy foods and red meats,” said Dr Nurulamin Noor, a clinical lecturer in gastroenterology at the University of Cambridge and Cambridge University Hospitals. The diet is rich in vegetables, fruits, legumes, nuts, seeds, fish and olive oil, with low intakes of meat and dairy, and is associated with a lower risk of bowel cancer and improved gut bacteria balance.
Verma emphasised moderation: “If you’ve had a heavy, rich meal one day, then the next day have something a bit lighter, so it can recover from the excesses.”
Lifestyle factors that shape gut health
Beyond diet, lifestyle choices play a fundamental role in digestive wellbeing. The gut and brain are in constant communication, said Patel, and stress “can speed up or slow down gut motility. It can heighten pain sensitivity, and trigger bloating and cramping. In some people, it can alter the microbiome as well.” Managing stress “isn’t soft advice: it really is the core of good health,” she said. To address stress, she recommended “slow, diaphragmatic breathing exercises that affect the nerves and signal to the gut to slow down or speed up.” Failing that, she suggested cognitive behavioural therapy and gut-directed hypnotherapy, which is recommended by NICE for managing irritable bowel syndrome and other functional gut disorders.
“We’re only starting to scratch the surface on how important the brain-gut connection is,” LeBrett said. “People always quote the fact that there are more serotonin receptors in your gut than there are in your brain. The same hormones and neurotransmitters that affect the brain can also impact the gut.” The UK has established research networks, such as the UK Gut-Immunology-Brain Axis Network+, dedicated to understanding how diet, sleep and stress influence this connection, which could lead to new treatments for mental health conditions and neurodevelopmental disorders.
Physical activity also promotes digestion. “I always recommend walking after a meal if you’re able to,” LeBrett said. “I walk after dinner; it helps to promote digestion and gets your body ready for sleep and rest as well.” The general exercise recommendation is 150 minutes per week, Patel said, with core strengthening exercises such as Pilates and yoga helping to “regulate the gut/brain axis” through diaphragmatic breathing.
Sleep is another priority. LeBrett has researched its impact on digestion: “Studies show that, in patients with IBS who had poor sleep, it was associated with worsened symptoms the next day.”
Oral health is an underappreciated factor. “The digestive tract is anywhere from your mouth to your bottom end,” said Noor. “We know that oral health is really important and probably has a major role in diseases lower down the gut, but it is relatively underappreciated.” Good oral hygiene, including brushing, flossing and regular dental visits, is advisable.
Smoking can cause reflux and increase the risk of bowel cancer, Verma warned. Smoking accounts for approximately 7% of bowel cancer cases in the UK, with risk increasing with the number of cigarettes smoked daily, and can lead to more aggressive polyps and disease recurrence after treatment. Quitting reduces the risk, with support available through the NHS Smokefree service. Regular, high alcohol consumption is also a risk factor, linked to about 6% of UK bowel cancer cases, as it exposes the body to cancer-causing chemicals that damage the digestive system.
Certain medications can harm the gut. LeBrett pointed to “nonsteroidal anti-inflammatory drugs (NSAIDs)” and advised against the overuse of antibiotics.
When it comes to probiotics, the evidence is mixed. “Some people swear by probiotics,” said Verma, “but we don’t have compelling evidence that they can be used for a wide variety of conditions. Probiotic yoghurt drinks are not expensive, so if someone taking them feels well on them, then it’s not an unreasonable step.” LeBrett said it is more important to focus on prebiotics — non-digestible fibres that feed beneficial gut bacteria — found in foods such as onions, garlic, asparagus, leeks, bananas, oats, beans, lentils and chickpeas. Probiotics may be considered for specific situations such as travel or preventing antibiotic-related diarrhoea, but they cannot replace a balanced diet.
Ultra-processed foods (UPFs) now constitute more than half of the average UK diet and are linked to increased risks of obesity, Type 2 diabetes, cardiovascular disease and cancer. Research indicates a 10% increase in heart disease risk for every 10% rise in UPF intake, and studies suggest diets high in UPFs can lead to weight gain and may be associated with increased risks of depression and anxiety. “We’re in a bit of a mess with bowel cancer,” said Verma, noting rising cases among people under 50, including high-profile figures such as Deborah James and Adele Roberts. “We are still not fully sure why these cancers are rising among younger people, but some have suggested, without concrete evidence, that ultra-processed foods may be a component of that.” He acknowledged that “it is virtually impossible to have a UPF-free diet,” but stressed balance: “Having a burger is not a terrible thing: having a burger twice a day, every day for a week, is a problem.”
When to see a doctor
Gastroenterologists stress that while minor digestive issues are common, certain symptoms warrant medical attention. “We can all have stomach bugs and get a bit of bleeding if we’ve got a sore bottom,” said Verma. “But if you have rectal bleeding or a change in your bowel habits that persists for three to four weeks or more, then you should get that checked out. Another red flag symptom is unintentional weight loss. If you suddenly lose half a stone, then it is always worth seeking medical advice.”
Bowel cancer screening is also crucial. In the UK, individuals aged 50 to 74 are sent a national screening faecal immunochemical test every two years. The FIT kit detects tiny amounts of blood in stool, which can be an early sign of polyps or bowel cancer. If blood is detected, an urgent colonoscopy is offered. The programme is gradually expanding to include younger age groups. Bowel cancer is the fourth most common cancer in the UK and the second biggest cause of cancer death, but early detection through screening significantly improves treatment outcomes and survival rates.
Patients often feel embarrassed discussing digestive symptoms, but Patel said this should not deter them. “We talk about it every day, and there is really no embarrassment on our side,” she said. “It is only a desire to help people feel better, put their mind at ease and to rule out anything serious. I always say to my patients that their symptoms really do matter, and they deserve to feel well. Getting help early is always the best step.”
As for the habit of scrolling on the toilet, the evidence is mixed. LeBrett noted that “there was a study that found scrolling on the toilet and smartphones in the toilet increases your risk of haemorrhoids, and can also cause pelvic floor dysfunction. Plus, it’s not very hygienic to have your phone in the bathroom.” Verma took a more relaxed view: “A direct link between phone use and bowel issues has not been proven and perhaps may be a simple association. Those who need to spend a lot of time in the loo will often use their phone to pass the time.”
