Fascinated by fibremaxxing? Your personalised fibre prescription

New Australian research suggests that dietary fibre could be used like precision medicine. By matching your digestive symptoms to the unique characteristics of certain fibres, you (and your gut) might find greater success.

Most of us don’t eat enough fibre, despite its positive links to digestion, cancer prevention, heart health and blood sugar regulation, important for energy, mood and healthy weight. Current wellness trends like ‘fibremaxxing’ (significantly increasing your fibre intake) are great for fibre’s image, but can lead to bloating, wind and cramps – especially if you already have digestive issues.

Most of us understand fibre at its simplest: soluble or insoluble. But new research from RMIT University suggests that this classification doesn't tell the whole story. In fact, different fibres have very different effects on symptoms like bloating, diarrhoea and constipation.

The researchers propose that fibres should be classified according to how they behave in the gut, including how much water they hold, how quickly they're fermented by gut bacteria and how well they maintain their structure as they move through the digestive tract. This could help explain why high-fibre foods work well for one person, but can make someone else's symptoms worse.

For people living with chronic digestive conditions like IBS or frustrating symptoms like bloating or constipation, it's a step towards more personalised nutrition advice and one that I already take in the pip nutrition clinic. Here are three practical examples:

If loose stools are your main concern, fibre that holds onto water may help firm stool consistency. Foods rich in this type of fibre include oats. Try my quick snack recipe for cranberry oat bites, or download a free extract of my cookbook, The Sunlight Sets, from the pip nutrition homepage to get a recipe for rose raspberry overnight oats, delicious, easy and delicately flavoured.

If constipation is the issue, fibres that retain their structure in the bowel can help stimulate movement. A simple option is ground linseeds (also known as flaxseed meal), just a teaspoon sprinkled over your morning yoghurt or porridge or added to smoothies. Buy a bag from the supermarket and store it in the fridge.

If bloating or wind is your biggest challenge, slower-fermenting fibres can be easier for your gut to tolerate because they produce gas more gradually. Try foods containing resistant starch. Cooling some carbohydrate-based foods, such as potatoes, after cooking increases their resistant starch levels. Make the baby potato salad with fennel sourdough crumb from my website and enjoy it for lunch this weekend.

When you’re adding fibre to your diet, always increase it gradually, for example by an extra half serve every week, and drink extra fluids. This supports your digestive system and reduces the chance of constipation and bloating.

Many people turn to a high fibre diet when they start experiencing digestive problems, but it can be ‘too much of a good thing’ and make symptoms worse. The take-home message I share every week in my clinic?

Yes, you need fibre to stay regular and keep your bowel healthy. But rather than focusing on eating more fibre, consider the right type of fibre for you.

With my help, your personalised fibre prescription can have a significant effect on your digestive health. And as research in this space develops, it could help make fibre recommendations far more targeted and effective.

Like research? Read ‘Beyond soluble and insoluble: A comprehensive framework for classifying dietary fibre’s health effects’ is published in Food Research International. DOI: 10.1016/j.foodres.2025.115843

Author: Kym Lang. Image: Wix.