Reviewed Harriet Smith, Registered Dietitian
Up your daily fibre intake to 30g a day – that’s the latest nutritional advice from the British government for anyone over the age of 17 (1).
‘Dietary fibre’ is one of those terms you encounter in supermarket ads for breakfast cereals promising you a ‘healthy start to your day’. But what is fibre and why is it good for us?
Welcome to Fibre: 101, all your fibre-related questions addressed in one bite-sized chunk – no pun intended!
So, what is dietary fibre?
Let’s get the science-y stuff out the way first.
Simply put, dietary fibre refers to the parts of plant-based foods that aren’t broken down by our digestive systems. It comes in two main forms – soluble and insoluble fibre – both of which are found in varying proportions in foods like fruits, vegetables and whole grains.
Soluble fibre, commonly found in foods like oats, citrus fruits, and avocado, readily dissolves in water to form a gel-like substance in the intestine. Ever noticed the gluey texture of freshly made porridge – that’s soluble fibre in action!
Soluble fibre acts like a sponge, mopping up any excess water from your digestive tract. This slows the rate at which food passes through your digestive system and softens the stools, allowing them to pass easily. It also helps to reduce high blood sugar levels after carbohydrate-rich meals, maintain healthy cholesterol levels (2), and may even improve satiety (fullness) levels (3).
Insoluble fibre does not dissolve in water and is commonly found in nuts and seeds, whole grains, beans and legumes, root vegetables and the skins of fruit (always eat your peel, kids!). Insoluble fibre stays intact as it passes through the gut during digestion. It bulks out our stools, absorbs fluids and mops up other by-products of digestion, which helps to prevent constipation (4) and diverticular disease (5).
A diet rich in fibre has been associated with a reduced risk of developing chronic conditions such as heart disease and type 2 diabetes (6, 7). So it makes sense to ensure you’re getting enough in your diet!
How to optimise your gut health
One of the best ways to maintain a healthy and diverse gut microbiome is through eating a diet which is high in fibre. The term ‘microbiome’ refers to the diverse spectrum of microorganisms (mainly bacteria) existing on and within you (8).
High-fibre foods are healthy foods for gut health. Fibre feeds the microbes in your gut, helping them to thrive and multiply in numbers. Both soluble and insoluble fibre have been found to play a key role in supporting the health of your microbiome.
Healthy foods for gut health
What are healthy foods for gut health and how much should you be eating? When it comes to eating a fibre-rich diet, variety is key. To reach the 30g fibre a day recommendation, eat plenty of high-fibre foods such as fruits, vegetables, whole grains and nuts and you’ll probably be knocking those guidelines right out of the park. That said, the average British adult is currently only eating 18g of fibre per day (9), 12g below the guidelines!
To help you out, we have come up with a list of some common high fibre food:
|Food (Serving Size)||Fibre (g)|
|Carrot (1 medium, raw)||4.0|
|Apple (1 medium, with skin)||2.3|
|Artichoke (1 medium, cooked)||10.3|
|Raspberries (1 cup)||8.0|
|Avocado (½ medium)||6.7|
|Sweet potato, (1 medium, cooked)||3.8|
|Bell pepper (1 cup)||3.0|
|Baked beans (½ cup)||6.6|
|Lentils (¾ cup)||6.2|
|Almonds (⅓ cup)||4.0|
If you’re looking for help in increasing your fibre intake, the Reset Your Health Plan could help. We’ll create a bespoke high-fibre meal plan tailored to your preferences and medical and nutritional requirements.
1. SACN. Carbohydrates and Health. TSO Station Off. 2015;
2. Aller R, De Luis DA, Izaola O, La Calle F, Del Olmo L, Fernandez L, et al. Effect of soluble fiber intake in lipid and glucose leves in healthy subjects: A randomized clinical trial. Diabetes Res Clin Pract. 2004;
3. Burton-Freeman B. Dietary Fiber and Energy Regulation. J Nutr. 2000;
4. Erdogan A, Rao SSC, Thiruvaiyaru D, Lee YY, Coss Adame E, Valestin J, et al. Randomised clinical trial: mixed soluble/insoluble fibre vs. psyllium for chronic constipation. Aliment Pharmacol Ther. 2016;
5. Threapleton DE, Greenwood DC, Evans CEL, Cleghorn CL, Nykjaer C, Woodhead C, et al. Dietary fibre intake and risk of cardiovascular disease: Systematic review and meta-analysis. BMJ. 2013.
6. Pereira MA, O’Reilly E, Augustsson K, Fraser GE, Goldbourt U, Heitmann BL, et al. Dietary Fiber and Risk of Coronary Heart Disease: A Pooled Analysis of Cohort Studies. Arch Intern Med. 2004;
7. Schulze MB, Schulz M, Heidemann C, Schienkiewitz A, Hoffmann K, Boeing H. Fiber and magnesium intake and incidence of type 2 diabetes: A prospective study and meta-analysis. Arch Intern Med. 2007;
8. Ursell LK, Metcalf JL, Parfrey LW, Knight R. Defining the human microbiome. Nutr Rev. 2012;
9. Fibre: Food Fact Sheet [Internet]. British Dietetic Association. [cited 08 May 2020] Available from: https://www.bda.uk.com/resource/fibre.html