What Is Fibermaxxing?
If you’ve been on TikTok or Instagram in the past year, you’ve likely seen the term "fibermaxxing". This trend promotes a significant increase in fibre consumption to support health and wellbeing.
Although the scientific evidence regarding a high-fibre diet is solid, social media often lacks nuance. So, is it a genuine health win or just another passing wellness fad?
As with most things in nutrition, it depends.
The right amount, the right type, and the right pace of increasing fibre can look very different from one person to the next. As a gut health dietitian, I work with people every day for whom fibre is a powerful tool. I also work with people for whom the wrong approach to fibre has made their symptoms considerably worse. So let's look at both sides.
What Even Is Fibre, and Why Does It Matter?
Dietary fibre is a type of carbohydrate found in plant foods, such as whole grains, fruits, vegetables, pulses, nuts, and seeds. Unlike other carbohydrates, it isn't digested or absorbed in the small intestine. Instead, it travels to the large intestine, where it does a great deal of important work (1).
If you've read my previous post on continuous glucose monitors, you'll know how important it is to avoid sharp glucose spikes. Soluble fibre is an effective tool for controlling this: by slowing gastric emptying, it helps flatten the post-meal blood curve and supports steadier energy levels (2).
The long-term benefits are documented in major research, including reviews in The Lancet. High fibre intake is linked to a 15-30% reduction in cardiovascular mortality, reduced rates of coronary heart disease, stroke, lower rates of type 2 diabetes, and colorectal cancer (3). Fibre also feeds beneficial gut bacteria that produce short-chain fatty acids like butyrate, which helps manage inflammation and support immune function (4,5).
- You’ll learn to interpret your symptoms clearly, turning unpredictable flare-ups into patterns you can manage with confidence.
The UK Fibre Gap Is Real
According to the National Diet and Nutrition Survey, average fibre intake among UK adults stood at approximately 18g per day in 2019, with only 9% meeting the recommended 30g daily target (6). The most recent edition of the same survey reveals that this gap has since widened: mean intake has fallen to 16.6g per day, and just 4% of adults are now meeting the recommendation (7).
More Isn't Always Better
Fibermaxxing, like most social media nutrition trends, isn't without its pitfalls.
Digestive Adaptation
Even for people without any digestive conditions, the gut simply needs time to adapt to a significantly higher fibre intake. The BDA recommends increasing intake gradually to allow the digestive system to adapt (1). Abruptly adopting a high-fibre diet may result in bloating, flatulence, cramping, and even constipation.
Hydration Dependency
Fibre draws water into the bowel, which is part of how it supports digestive regularity. But this means that significantly increasing your fibre intake without a corresponding increase in fluid can actually worsen constipation rather than relieve it.
Diet Culture
The "maxxing" framing is worth highlighting: it implies there is a target to hit, a number to optimise, and a failure state if you don't reach it. Rigid dietary rules, even those framed around health, can reinforce all-or-nothing thinking and a moralised relationship with food.
IBS + FODMAPs
If you have IBS, the "eat more fibre" message isn't quite as straightforward; following 'fibremaxxing' trends without professional guidance could significantly exacerbate your symptoms. Many high-fibre foods are also high in FODMAPs - fermentable carbohydrates that are poorly absorbed in the small intestine. These can trigger bloating, flatulence, cramping, and altered bowel habits in individuals with sensitive guts ( 8,9).
While these do not necessarily need to be avoided indefinitely, consuming them in large quantities can cause significant distress. Conversely, lower-FODMAP fibre sources are typically better tolerated and represent a safer starting point. (9) The goal is never restriction for its own sake. It's about understanding which fibre sources work for your unique gut, then gradually reintroducing foods to build as broad and nourishing a diet as possible.
IBD and Other Conditions
Similarly, individuals with inflammatory bowel disease (IBD) during a flare, or those preparing for specific medical procedures, may be advised to follow a temporary low-fibre diet. If you have any digestive health conditions, always consult your GP or a registered dietitian before making significant dietary changes.
Fibre management in IBS is nuanced. While a fibre-rich diet remains the long-term goal, it must be the right type of fibre, introduced at the correct pace, with professional support. If this resonates with you, consulting a dietitian specialising in gut health can make a significant difference.
Medication Interactions
If you take regular medication, particularly levothyroxine for an under active thyroid, it's worth knowing that high fibre intake, especially from supplements, may affect how well your body absorbs it (10). This doesn't mean you need to avoid fibre, but timing matters: taking medication well before a high-fibre meal can make a real difference. The goal is never restriction for its own sake. It's about understanding which fibre sources work for your unique gut, then gradually reintroducing foods to build as broad and nourishing a diet as possible.
How to Increase Fibre Sensibly (If It's Right for You)
This isn't about restriction, tracking, or hitting a number. There are some genuinely simple, satisfying ways to close the fibre gap: Go slow. Think of it as a slow introduction rather than a makeover. This gives your gut time to adapt and reduces the risk of discomfort (1).
- Swap refined grains for wholegrain or wholemeal versions. Bread, pasta, rice, and oats are all easy places to start. One swap at a time is all it takes.
- Add pulses to meals you already love. Lentils in a Bolognese, chickpeas in a curry, kidney beans in a soup. They're affordable, filling, and fibre-rich.
- Aim for variety in your five-a-day. Different fruits and vegetables feed different gut bacteria, so rather than eating the same high-fibre foods on repeat, aim to rotate and explore (4).
- Keep the skin on where possible. Potatoes, parsnips, apples, and carrots all carry fibre in their skins, and it saves time too.
- Snack on nuts, seeds, or fruit. A small handful goes a long way as an afternoon pick-me-up alongside your usual meals.
- Stir chia seeds or ground flaxseed into porridge or yoghurt. One of the simplest, most low-effort ways to add fibre to your day.
- Drink more water alongside. Increasing your fibre intake without increasing your fluids can backfire.
A Dietitian's Take on Fibermaxxing
Most people in the UK would genuinely benefit from eating more fibre. The gap between what we consume and what we need is real, and closing it matters for long-term health. What is genuinely appealing about fibermaxxing, at its core, is that it is additive rather than restrictive. Rather than cutting things out, it is about what can be brought in. It is not a restriction that serves us in the long run, it is nourishment.
But "maxxing" is not the answer for everyone, and personalisation is key. What works beautifully for one person can cause real discomfort for another, depending on their gut health, their relationship with food, and where they are starting from. Food is so much more than a vehicle for nutrients. It is about pleasure, connection, culture, and feeling good in your body.
Think of it as fibre-reaching rather than fibermaxxing. Aiming steadily for that 30g daily target, building gradually, keeping variety at the heart of it, and listening to the body along the way. That is not a trend. That is just really good, evidence-based nutrition.
These small shifts add up naturally over time. If you'd like support building a way of eating that genuinely works for your body, whether you're navigating IBS, a more complex relationship with food, or simply wanting to feel your best. I'd love to help.
Meet Kirsty Wood
Specialist Gut Health Dietitian – Isle of Wight
Kirsty Wood is a Registered Dietitian (BSc Nutrition & Dietetics) with over 9 years’ experience helping people overcome food intolerances, IBS, and gut-related issues. She has worked in both NHS and private practice.
Based on the Isle of Wight, Kirsty offers a Gut Health Programme called the IBS Relief Method™ . The 1:1 programme blends evidence-based nutrition with structured support to help you move from frustration to freedom.
Dietitian / Nutritionist Clinic Locations on the Isle of Wight:
- 81 George Street, Ryde, PO33 2JF
- 34 The Mall, Newport, PO30 1BW
- Online (UK-wide)
Start building a calm, confident relationship with food, supported by a trusted professional.
References
- British Dietetic Association (BDA). (2023). Fibre Food Fact Sheet. Available at: https://www.bda.uk.com/resource/fibre.html
- Weickert, M.O. and Pfeiffer, A.F.H. (2018). Impact of Dietary Fiber Consumption on Insulin Resistance and the Prevention of Type 2 Diabetes. Journal of Nutrition, 148(1), pp.7–12. doi: https://doi.org/10.1093/jn/nxx008
- Reynolds, A., Mann, J., Cummings, J., Winter, N., Mete, E. and Te Morenga, L. (2019). Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet, 393(10170), pp.434–445. doi: https://doi.org/10.1016/S0140-6736(18)31809-9
- Mukhopadhya, I. and Louis, P. (2025). Gut microbiota-derived short-chain fatty acids and their role in human health and disease. Nature Reviews Microbiology, 23, pp.635–651. doi: https://doi.org/10.1038/s41579-025-01183-w
- Baxter, N.T., Schmidt, A.W., Venkataraman, A., Kim, K.S., Waldron, C. and Schmidt, T.M. (2019). Dynamics of human gut microbiota and short-chain fatty acids in response to dietary interventions with three fermentable fibers. mBio, 10(1), e02566-18. doi: https://doi.org/10.1128/mBio.02566-18
- Public Health England. (2020). National Diet and Nutrition Survey: Years 9 to 11 of the Rolling Programme (2016/2017 to 2018/2019). London: Public Health England. Available at: https://assets.publishing.service.gov.uk/media/5fd23324e90e07662b09d91a/NDNS_UK_Y9-11_report.pdf
- UK Health Security Agency; Food Standards Agency. (2025). National Diet and Nutrition Survey: 2019 to 2023. London: UK Government. Available at: https://www.gov.uk/government/statistics/national-diet-and-nutrition-survey-2019-to-2023/national-diet-and-nutrition-survey-2019-to-2023-report#nutrient-intakes
- Staudacher, H.M. and Whelan, K. (2017). The low FODMAP diet: recent advances in understanding its mechanisms and efficacy in IBS. Gut, 66(8), pp.1517–1527. doi: https://doi.org/10.1136/gutjnl-2017-313750
- McKenzie, Y.A., Thompson, J., Gulia, P. and Lomer, M.C.E. (2016). British Dietetic Association systematic review and evidence-based practice guidelines for the dietary management of irritable bowel syndrome in adults. Journal of Human Nutrition and Dietetics, 29(5), pp.549–575. doi: https://doi.org/10.1111/jhn.12385
- Wiesner, A., Gajdzik, L., Więcek, A. and Nowak, J.K. (2021). Levothyroxine Interactions with Food and Dietary Supplements — A Systematic Review. Pharmaceuticals, 14(3), 206. doi: https://doi.org/10.3390/ph14030206
