Credit: Getty
Strong Women
PSA: this is what happens inside your gut when you don’t eat enough fibre
By Lauren Geall
3 months ago
5 min read
Eating enough fibre is incredibly important for our gut health, but many of us aren’t eating enough of it. So, what actually happens inside the gut when our fibre consumption is low? Experts explain.
Despite all the hype surrounding gut health over the last couple of years, many of us are still much more concerned about our protein intake than we are with how much fibre we’re eating.
According to research into the UK’s dietary habits, just 9% of us consume the recommended 30g of fibre every day, with the average adult consuming just 20g.
That’s a problem, because not only do the foods that are high in fibre – such as fruits, vegetables and whole grains – contain a wide range of beneficial nutrients, but eating a diet lacking in fibre can have a detrimental effect on your gut health. To find out more, we’ve been speaking to the experts.
How does our gut use fibre?
Credit: Getty
Delivering plenty of fibre to our gut can have numerous health benefits. From a physical perspective, fibre is bulky, and as a result, it helps to carry things through the gut so they can be excreted.
Fibre – particularly prebiotic fibre – is also fuel for our gut bacteria. “Fibre helps to maintain a healthy balance of gut bacteria by providing food for the good bacteria and creating a slightly acidic environment in the colon, which inhibits harmful bacteria from thriving,” says Rob Hobson, a nutritionist from Bio-Kult. “This relationship between fibre and gut bacteria is essential for keeping your gut barrier strong and protecting against conditions linked to microbial imbalances, known as dysbiosis.”
As they feast on fibre, our gut bacteria also produce several beneficial compounds that help to maintain gut health, including short-chain fatty acids (SCFAs) such as butyrate acetate and propionate. These help to nourish the gut lining, reduce inflammation and support the immune system.
This process also leads to the production of hormones, neurotransmitters and even vitamins, all of which either play a role in the gut or travel around the body to be used elsewhere.
What happens to our gut when we don’t eat enough fibre?
Because fibre plays such an essential role in maintaining our gut health, not eating enough can quickly wreak havoc. Firstly, without the bulk that fibre provides, the digestive process can be affected.
“When you don’t eat enough fibre, your gut doesn’t get the roughage needed to help waste move smoothly through the digestive tract,” says Riya Lakhani-Kanji, in-house nutritionist for Nutravita. “This can slow down digestion, often leading to discomfort and constipation, and over time, this can upset the delicate balance of your gut bacteria.”
Failing to fuel your gut bacteria can also have consequences. Not only will you limit or stop the production of short-chain fatty acids and other beneficial compounds, but failing to give your gut bacteria the fibre they need can cause them to die off or look for other food sources.
“If we don’t feed our gut bacteria, they end up eating the mucin lining of our gut,” Dr Federica Amati, head nutritionist at Zoe, recently told us at Stylist Live. “The mucin lining is this snot-like substance that protects the lining of our gut, and if we’re not feeding our gut with fibre, they will turn to eating the mucin instead. And this can cause inflammation.”
What impact can this have on our wider health?
The gut shares links with almost every other system in our body, so you won’t be surprised to learn that harming your gut health by not eating enough fibre can have a knock-on effect elsewhere.
For one thing, our gut actually plays a key role in regulating our hormonal balance (a group of gut bacteria known as the estrobolome help to rid the body of excess oestrogen), so failing to support this group of bacteria with plenty of fibre can lead to hormonal imbalance.
When your fibre intake remains low, the inflammation triggered by the gut bacteria eating your mucin lining can also become chronic – a risk factor for diseases such as heart disease and colorectal cancer.
“Additionally, a diet lacking in fibre which disrupts the balance of the gut bacteria can have a knock-on effect on the immune system, as much of it is regulated in the gut,” Hobson says.
“This can leave you more vulnerable to infections, especially at this time of year. And there’s also a growing body of research showing how gut health impacts mental health through the gut-brain axis, meaning a low fibre intake might even play a role in mood disorders like anxiety and depression.”
Signs you’re not eating enough fibre
Credit: Getty
Fibre can be found in foods ranging from fruits and vegetables to whole grains, nuts and seeds and legumes (the richest source of dietary fibre and one that can provide a third of your daily intake in half a can, according to Hobson) – so there are plenty of ways to up your intake. However, if you’re not getting enough fibre, you might notice some signs or symptoms that indicate you need to make a change. These include:
1. Constipation, bloating and digestive discomfort
“Constipation is one of the most common issues that occurs when fibre intake is low, as fibre is essential for adding bulk to stool and promoting regular bowel movements,” Hobson says. “People may also experience bloating and abdominal discomfort, often caused by slower digestion or an imbalance in gut bacteria, which can lead to gas build-up.”
2. Blood sugar-related energy fluctuations
“A low-fibre diet may also cause blood sugar levels to fluctuate more dramatically, potentially resulting in fatigue and low energy,” Hobson explains. This is because soluble fibre – found in apples, bananas, oats, black beans and avocados, among other sources – helps to slow down the absorption of sugar by producing a gel-like substance in the gut. It does this by absorbing water.
3. Feeling hungry all the time
“Fibre plays an important role in helping you feel full and satisfied after meals, so without it you may feel hungrier and more likely to crave high-sugar or high-fat foods,” Hobson says. This can contribute to overeating and, over time, may lead to weight gain, as fibre-rich foods are often less energy-dense and help regulate appetite.”
Images: Getty
A weekly dose of expert-backed tips on everything from gut health to running, plus receive our 8-week beginner’s guide to strength training.
By signing up you agree to occasionally receive offers and promotions from Stylist. Newsletters may contain online ads and content funded by carefully selected partners. Don’t worry, we’ll never share or sell your data. You can opt-out at any time. For more information read Stylist’s Privacy Policy
Thank you!
You’re now subscribed to all our newsletters. You can manage your subscriptions at any time from an email or from a MyStylist account.