‘Fibremaxxing’ is all the rage on social media, but while many people today get far less fibre in their diets than the 20-35g a day recommended by South Africa’s Food Advisory Consumer Service1, very high intakes can have adverse effects.
“As in many trends seen on social media, getting accurate information and applying caution, moderation and balance are key,” says Johannesburg-based dietitian Lila Bruk.
What is fibre?
Fibre is a carbohydrate in plants that cannot be fully digested, passing through the digestive tract to your large intestine. There are two main types.
Insoluble fibre, such as cellulose (found in whole grains, for example), does not dissolve, but rather adds bulk to stool and aids movement through the digestive system, says Bruk.
Soluble fibre, such as pectin and beta-glucan (in fruit and vegetable peels, oats and legumes), dissolves in water to form a gel and helps lower cholesterol and blood sugar.
“Soluble fibre also supports the growth of beneficial gut bacteria,” she says. These microbes produce short-chain fatty acids with anti-inflammatory and protective functions, seeming to lower the body’s insulin response and slow the absorption of glucose – especially beneficial for those with diabetes. They lower total and ‘bad’ LDL cholesterol, reducing the risk of heart disease, and may also help reduce the risk of colon cancer.
There is emerging evidence2 that fibre can affect brain functioning, cognition and mood, and it promotes a feeling of fullness, supporting weight regulation in the long term.
Why you may need more fibre
The World Health Organisation reports3 that changes in food production and food systems, rapid urbanisation and changing lifestyles have led to a shift in dietary patterns. In general, we’re eating more ultra-processed foods high in unhealthy fats, free sugars and salt, and many people do not eat enough fruit and vegetables or consume sufficient dietary fibre.
“Low-carb diets, which are relatively popular, can also decrease fibre intake,” says Bruk.
The dangers of too much fibre
Some ‘fibremaxxing’ promoters on TikTok advocate well beyond the maximum 35g of fibre a day advised by dietitians – some as much as 50 and 100g a day, often not just from fibre-dense foods, but from supplements or powders. However, too much fibre can be harmful, Bruk says.
It’s possible for it to displace other vital food groups such as proteins, carbohydrates and healthy fats. Consuming too much fibre too fast without enough water can lead to bloating, cramping, flatulence, constipation and even intestinal blockage, she cautions. In addition, some types of dietary fibre can bind to important minerals (like zinc, iron, and calcium) and impede their absorption.
5 healthy ways to increase your fibre intake
1. Do it gradually, to the recommended level – not beyond 35g a day, says Bruk.
2. Use natural food sources by having a balanced, varied diet with whole grains, vegetables, fruits, pulses, nuts and seeds.
3. Simple adjustments can be all it takes: replace white bread, rice and pasta with seed bread, brown rice and wholewheat pasta. Keep skin on fruits and vegetables where possible. Add legumes (beans, peas, lentils) to stews and soups. Enrich your breakfast with oats or flaxseed and fresh fruit, top up your lunch by adding pulses such as chickpeas or kidney beans to salads, and boost dinner by having whole-grain carbs and fibre-rich vegetables such as broccoli, butternut, sweet potato and carrots. Snack on a small handful of pumpkin seeds, raw nuts and dried fruit between meals. “Just be careful of the sugar content of dried fruit,” says Bruk.
4. Drink plenty of water (around 8 to 12 glasses a day) – too little can lead to constipation if you’ve increased your fibre intake.
5. Take care if you have inflammatory bowel conditions (such as Crohn’s disease or ulcerative colitis) or irritable bowel syndrome, as high fibre can worsen their symptoms. Speak to your healthcare professional, and get their advice if you have unexplained stomach pains, constipation or diarrhoea. If possible, work with a dietitian for a personalised eating plan that suits your condition, tastes and lifestyle.
References
1. https://foodfacts.org.za/fibre-in-foods/
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC11406392/
3. https://www.who.int/news-room/fact-sheets/detail/healthy-diet
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