You may have heard of ‘fibremaxxing’. The recent health trend has been popularised on social media platforms like TikTok and involves people increasing their daily fibre intake dramatically – often well beyond the recommended amount of 25–30g (0.9–1oz) per day – with the aim of improving their gut health.
Influencers have been hailing fibre as the “new protein” and loading up on high-fibre foods such as beans, lentils, whole grains, fruits and vegetables, and even taking extra fibre supplements to hit their elevated daily consumption targets.
The theory is that doing so has a suite of health benefits. It’s said to improve digestion, help to make bowel movements more regular, increase gut bacteria and potentially help ease the symptoms of irritable bowel syndrome (IBS).
The trend has grown out of the belief that modern diets don’t provide us with enough fibre and there is a grain of truth to that.
Indeed, the most recent data shows that 91 per cent of people in the UK fall short of the recommended target for the nutrient and the same is true in the US, where national consumption surveys show that 95 per cent of people aren’t getting enough fibre.
As such, increasing your consumption of fibre should be a good thing, right? Well, as with most things when it comes to diet and health, it’s not that simple.
Gut reaction
Fibre is crucial for the gut for several reasons.
It’s a carbohydrate, but unlike other carbohydrates, such as starch and sugar, fibre isn’t digested and absorbed in the small intestine. Instead, it passes through into the large intestine, where it’s broken down and consumed by the bacteria that live there. Feeding these bacteria can lead to a range of health benefits, as they produce short-chain fatty acids (SCFAs) that benefit our bodies.
The fibre that isn’t broken down absorbs fluid and increases the bulk of waste matter, making our stools softer and easier to pass. Increasing the nutrients in your diet can therefore help you avoid constipation and keep your bowel movements regular.
Some people with IBS find that increasing fibre can help ease their symptoms, especially if they suffer more from constipation than diarrhoea.
Vegetables contain a mix of different fibres, including soluble and insoluble, that are beneficial to gut health
There’s some evidence that having enough fibre in the diet can reduce your risk of colon cancer, too. One of the SCFAs produced in the large intestine is butyrate, which is thought to have anti-inflammatory and protective effects on colon cells.
By moving the stool along, fibre also reduces the time that the colon cells in the lining of the gut are exposed to harmful substances. It’s thought that one of the reasons behind the rise in colon cancer worldwide, especially in younger people, is a reduction in the consumption of fibre-rich foods.
But while getting more fibre into your diet is generally a good thing, ‘fibremaxxing’ takes good nutrition to an extreme – it’s like making your gut run a marathon it didn’t sign up for.
Too much of a good thing
The gut is a complex ecosystem that’s carefully balanced, and suddenly flooding it with more of one particular nutrient can have unintended consequences. Some ‘fibremaxxers’ are encouraging people to hit more than 50g (1.8oz) of fibre a day, which can lead to side effects such as bloating, cramps and diarrhoea.
There are also different types of fibre to consider. Soluble fibre absorbs water in the gut and slows digestion, whereas insoluble fibre passes through the gut largely intact and can help to speed up digestion. There are also those fermentable fibres that feed the bacteria in our large intestine.
We need a healthy balance of all of these to thrive. Too much insoluble fibre (found in wheat bran and some vegetables) adds bulk to stool, but can irritate sensitive guts. There are also certain types of fibre – fermentable, oligosaccharides, disaccharides, monosaccharides and polyols (known as FODMAPs) – that the gut can struggle to absorb and which can worsen the symptoms of IBS.
We need to balance the different types of fibre we consume, because they work together to support a well-functioning gut. By trying to hit extremely high targets like 50g (1.8oz) a day, ‘fibremaxxers’ might be tempted to eat a limited range of foods with the highest amount of fibre in them.
For example, high-fibre breakfast cereals can contain as much as 12.4g of fibre per 100g (0.5oz per half cup), and to hit their high targets, people might be tempted to consume multiple bowls a day. But while cereals are a great source of insoluble fibre, they’re not as good a source for soluble and fermentable fibre.
Overdoing fibre in our diets, without thinking carefully about how to balance the various types we need, might actually lead to more digestive discomfort and disrupt the delicate balance in the gut needed for the ecosystem to thrive.
Cleanse culture
By increasing just one kind of nutrient in the diet to glean specific health effects, fibremaxxing is the latest in a long line of cleanse and detox trends designed to target digestive health.
Different types of gut cleanses often crop up on social media, and while they might sound appealing, they’re often doing more harm than good. Juice cleanses, for example, can end up depriving you of essential nutrients, while ‘detox’ teas and laxatives can lead to dehydration, potentially damaging the lining of your gut in the long term.
There have been social media trends around the use of enemas, too, but these can disrupt the natural rhythm of the bowel and flush out all your good bacteria.
Juice cleanses are not a healthful or safe approach to dieting or weight loss
Experts recommend being wary of fad supplements or extreme elimination diets that cut out whole food groups without proper guidance. These can reduce the diversity of your microbiome and negatively impact digestion. Your gut won’t thank you for these dramatic resets – it just needs continued, careful, balanced support.
Gut watch
So, how can you tell if you’re getting enough fibre in your diet, and if you need to increase your consumption of it?
Fatigue and weight gain will usually be the first warning signs. Soluble fibre slows digestion – it keeps you feeling fuller for longer while gradually drip-feeding sugar into your bloodstream throughout the day.
Without it, your blood sugar levels can peak and drop haphazardly, leading to periods of fatigue shortly after eating. Drops in energy levels, like this, can make you more tempted to snack and cause you to gain weight.
Fibremaxxing may have started as a well-intentioned effort to improve our wellbeing, but like many viral health trends, it often oversimplifies a complex process and risks taking things too far.
There’s no doubt that most people would benefit from eating more fibre, especially from whole plant foods, and that doing so can support digestion, reduce the risk of disease and help maintain a healthy weight. But more isn’t always better – particularly if it’s sudden, excessive or unbalanced.
Your gut is a finely-tuned ecosystem that thrives on variety, consistency and balance – not dramatic overhauls or quick fixes.
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