Fibremaxxing: why more fibre is not always better

You need fibre – that is undeniable. Yet amid online health trends, sensible nutritional guidance has evolved into “fibremaxxing”: an encouragement to eat exceptionally large quantities in pursuit of better health.

NHS guidance in the UK recommends that adults consume at least 30g of fibre each day. The requirements for children and teenagers are generally considerably lower.

Despite these straightforward recommendations, most people in Britain do not reach their daily fibre goal.

A key reason is the growing prevalence of ultra-processed foods (UPFs). More than 54% of UK adults’ daily calorie intake now comes from ultra-processed foods; among teenagers, the figure is closer to 66%.

Ultra-processed foods and fibre intake

This is significant because UPFs tend to contain little fibre or few micronutrients, yet are often rich in sugar, salt and unhealthy fats. As these products take up more room on our plates, naturally fibre-rich whole foods are crowded out.

Research indicates that higher consumption of ultra-processed foods is associated with lower fibre intake, alongside reduced consumption of other vital nutrients. Consequently, much of the population remains well below the recommended daily fibre target.

As part of a balanced diet, dietary fibre is crucial to good health. Natural, plant-based foods are the best sources.

For an average person, including high-fibre foods in meals and snacks over a normal day could help meet the 30g daily recommendation. This might mean choosing wholegrain bread at breakfast, eating fruit such as an apple with its skin on, adding onions and lentils to a chilli for an evening meal, and having a handful of pumpkin seeds or Brazil nuts between meals.

Fibremaxxing and food displacement

The potentially harmful aspect of fibremaxxing is that other food groups – including protein, carbohydrates and fats – may be removed and replaced with fibre-heavy foods, powders or supplements.

This could mean that the risks outweigh the benefits of raising fibre intake. To my knowledge, no robust human studies have examined the long-term effects of consuming more than 40g of fibre per day. Some supporters of fibremaxxing recommend intakes of 50 to 100g daily.

Increasing fibre too sharply, particularly without drinking enough water, may cause constipation, cramps and bloating. It can also result in a build-up of gas, which may make an appearance at an awkward time – such as on the daily commute.

A sudden rise in fibre intake, or simply eating too much of it, can also disrupt the absorption of essential micronutrients such as iron, which helps the body function normally. It may similarly affect macronutrients, which supply energy for movement, repair and adaptation.

The benefits of a balanced high-fibre diet

That said, increasing dietary fibre can bring a broad range of health advantages. It helps maintain a healthy digestive system by encouraging regular bowel movements and reducing the incidence of inflammatory bowel disease.

Soluble fibre slows glucose absorption and therefore helps control blood sugar, making it particularly useful for people at risk of type 2 diabetes. It can also reduce LDL, or bad, cholesterol, lowering the risk of heart disease. Because fibre helps you stay full for longer, it can aid appetite regulation and healthy weight management. These benefits are all well established.

A diet high in fibre has also been associated with a reduced risk of some cancers, especially colon cancer, because it helps the body eliminate toxins efficiently. Raising fibre intake gradually to recommended amounts through a varied, balanced diet can deliver meaningful health benefits.

The available evidence makes it clear that many of us would benefit from eating more fibre – but only in moderation.

Until more is known, the safest approach is to remain within current fibre guidelines and choose natural food sources instead of powders or supplements. Fibre is essential, but more is not necessarily better. Ignore social-media fads and focus on balance: wholegrains, vegetables, nuts and seeds. Your gut – and your fellow commuters – will be grateful.

Lewis Mattin, Senior Lecturer, Life Sciences, University of Westminster

This article is republished from The Conversation under a Creative Commons licence. Read the original article.