The fibre deficit: why most Britons are falling short
More than nine in ten people in the UK are not consuming enough fibre, according to government-backed dietary surveys, despite mounting evidence that the nutrient is one of the most powerful tools for protecting long-term health. A 2023 report found that 96 per cent of British people aged 11 and over fail to meet the recommended daily intake of 25–35 grams, a figure that closely mirrors the equally poor fibre habits seen in the United States. Dr Wendi LeBrett, a California-based gastroenterologist, said the gap is so wide that some individuals need to take a fibre supplement simply to reach the target. “An apple has about 4g of fibre,” she said. “Then for lunch or dinner, a serving of beans can get you 5–6g of fibre.”
The consequences of that shortfall extend far beyond the gut. Fibre feeds the trillions of bacteria that make up the gut microbiome, a community now understood to influence mood, skin health and the immune system. “We know there is a strong association between how much fibre you have and a lower risk of getting colon cancer,” LeBrett said. “It has been shown to be beneficial for cardiometabolic health: it helps with blood sugar regulation, cholesterol and overall heart health.” Dr Ajay Verma, a consultant gastroenterologist at Kettering General Hospital in Northamptonshire, emphasised that people who increase their protein intake for muscle building often cut back on fibre, creating an imbalance. “Again, being mindful of balance is key,” he said. Even common discomforts such as excessive wind can be tackled through more fibre, he added, because “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”.
The challenge is not simply about eating more fruit and vegetables. LeBrett noted that a conscious effort is often required. Almonds, broccoli and oranges all contribute, but a serving of beans delivers 5–6 grams and a single apple around four grams. Verma pointed to kiwi as “one of the most effective dietary interventions for constipation” and recommended linseeds or flax seeds stirred into yoghurt as a cheap, natural laxative.
Dietary foundations: balance, variety and the Mediterranean model
A healthy gut, say the experts, is built on three pillars: balance, diversity and routine. Dr Nisha Patel, a consultant gastroenterologist and interventional endoscopist at Imperial College Healthcare NHS Trust in London, said the starting point is a diet high in fibre, fruit, vegetables, legumes and wholegrains, while avoiding irritants such as alcohol, caffeine, fatty or spicy foods and artificial sweeteners. “Large, late meals can also trigger gastrointestinal symptoms,” she added. Dr Nurulamin Noor, a clinical lecturer in gastroenterology at the University of Cambridge and Cambridge University Hospitals, said studies consistently show that a Mediterranean diet leads to better digestive health. “So 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.”
The issue of ultra-processed foods (UPFs) has become a particular concern amid a rise in bowel cancer cases among people under 50. High-profile cases such as Deborah James, who was diagnosed at 35, and BBC Radio 1 presenter Adele Roberts have brought the trend into public focus. The rate of bowel cancer diagnosis in those under 50 has increased by around 50 per cent since the mid-1990s. “We’re in a bit of a mess with bowel cancer,” Verma said. “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 stressed that a UPF-free diet is virtually impossible and that occasional indulgences are acceptable. “Having a burger is not a terrible thing: having a burger twice a day, every day for a week, is a problem. Make sure you are having regular meals, that a proportion of them are fresher, and you have plenty of fruit and vegetables.”
Red and processed meats carry their own risks. It is estimated that around 13 per cent of bowel cancer cases in the UK are linked to processed meats such as ham, bacon and sausages. The government recommends limiting intake to 70 grams or less per day. LeBrett said she restricts processed meats because of the strong colorectal cancer risk, though once in a while is fine. “I don’t buy it to cook at home.”
Lifestyle and the gut-brain axis: stress, sleep and movement
The gut and brain are in constant two-way communication, a connection known as the gut-brain axis. Patel called stress management “the core of good health” because stress can speed up or slow down gut motility, heighten pain sensitivity, trigger bloating and cramping, and even alter the microbiome. “It is often why people feel symptoms during certain stressful periods,” she said. The same hormones and neurotransmitters that affect the brain also affect the gut — indeed, there are more serotonin receptors in the gut than in the brain. To counter stress, Patel advocates slow, diaphragmatic breathing exercises that signal to the gut to regulate its activity. Failing that, she suggests cognitive behavioural therapy and gut-directed hypnotherapy. The National Institute for Health and Care Excellence (NICE) in the UK recommends gut-directed hypnotherapy for irritable bowel syndrome (IBS) when other treatments have failed. A UK research network has been launched to explore the gut-immune-brain connections further, aiming to develop new therapies for conditions ranging from anxiety to dementia.
Hydration is one of the simplest yet most underrated ways to stabilise digestion, Patel said, particularly when the gut is sensitive to stress. Water softens stool and supports its smooth movement through the colon. UK government advice suggests six to eight glasses — around 1.2 litres — of fluid per day, though this includes fluid from food. The European Food Safety Authority recommends a total water intake of two litres for women and 2.5 litres for men, with 70–80 per cent coming from drinks. Patel uses a water bottle that reminds her to drink 150–200ml every hour. Physical activity also plays a key role. LeBrett recommends walking after a meal to promote digestion. Official guidelines advise adults aged 19–64 to aim for at least 150 minutes of moderate-intensity activity per week, spread over four to five days, plus muscle-strengthening activities at least twice a week. Only 34 per cent of UK men and 24 per cent of women currently meet the strength-training target. Patel noted that core-strengthening exercises such as Pilates and yoga help with diaphragmatic breathing and regulate the gut-brain axis.
Sleep is another critical factor. LeBrett has researched its impact on digestion: studies show that patients with IBS who have poor sleep experience worsened symptoms the next day. Oral health, often overlooked, is also important because the digestive tract runs from the mouth to the anus. Noor said oral health “probably has a major role in diseases lower down the gut, but it is relatively underappreciated”. Brushing twice a day, flossing once a day and regular dental visits are advisable. Smoking is a significant risk factor for bowel cancer, accounting for about 7 per cent of cases in the UK, and Verma warned it can cause reflux and increase cancer risk. High alcohol consumption is also a major risk factor. Overuse of nonsteroidal anti-inflammatory drugs (NSAIDs) and antibiotics can harm the gut, LeBrett said. As for probiotics, Verma said the evidence for their widespread use is not compelling, though some people find them helpful. LeBrett added that it is more important to focus on prebiotics — the fruit, vegetables, wholegrains and legumes that feed the microbiome.
When to seek medical advice: red flags and screening
While occasional stomach bugs and minor bleeding from a sore bottom are common, persistent symptoms should prompt a doctor’s visit. “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,” Verma said. “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 offered every two years via a faecal immunochemical test (FIT) to everyone aged 50–74 in England, Scotland and Wales (Northern Ireland invites from age 60). Those aged 75 and over can request a test. If the test is positive, even without symptoms, patients are offered an urgent colonoscopy. Verma urged people to take up screening when offered.
Constipation affects an estimated one in seven UK adults and one in three children at any given time, with 84 per cent of people experiencing it in the last year. It is more common in women and older adults, and stigma often prevents open discussion. Verma stressed the importance of properly clearing the bowels after a poo — you should feel empty and not gassy or bloated. Squat stools can help by opening up the bowel. The frequency of bowel movements varies widely: Patel said normal can range from three times a day to three times a week, as long as it is consistent for the individual. Loo-scrolling — using a phone on the toilet — has been linked to an increased risk of haemorrhoids and pelvic floor dysfunction in one study, though Verma noted that a direct link has not been proven and those who need to spend time in the loo often use their phone to pass the time.
Patients frequently apologise for discussing digestive symptoms, Patel said. “There is really no embarrassment on our side. 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.”