Fibre – Why We Need More Of Nature’s Secret Ingredient – But Graduality Is Key!

by Marcelo Bravo 25th April 2019

Every day we’re bombarded with information about which diet to follow – low carb, low fat, high protein and more. But we often overlook fibre, a powerful superfood and key component of a healthy diet. Did you know that we are now eating less than a fifth of the amount of fibre we should be? 

But, it’s not just important to understand the health benefits of dietary fibre, we also need to know how to increase it within our diets!

Fibre refers to a diverse group of carbohydrates found naturally in plant foods that humans cannot digest. Fibre passes mostly intact into the large intestine where a proportion is fermented by gut bacteria, promoting the growth of beneficial bacteria in the gut (the “gut microbiome”).  We have been told for a long while now to eat foods rich in fibre, such as vegetables, pulses, fruits and whole grains. In recent years we have also begun to understand the benefits of different types of fibre and the role of fermentable (prebiotic) fibre in the maintenance of a healthy microbiome. Newly released University of Otago research recently published by The Lancet shows that not only this is true, but those foods are even better for you than scientists thought, and can contribute to lower risk of heart disease, stroke, diabetes and cancer.  Fibre is, indeed, very good for you.

Closing the “fibre gap”

The Lancet publication shows that most people in the comprehensive summary of systemic reviews, meta-analyses and clinical trials of the past 40 years ateless than 20 grams of fibre daily, and that an increase to at least 25 to 29g of fibre from foods daily produced significant health benefits.Noteworthy, these intakes are considerably below the estimated well over 100 grams per day that our ancestors were eating. The data unequivocally demonstrates that in our modern, Western diet we don’t get nearly as much fibre as we need and that a relatively modest increase delivers real benefits. Nutritionists call this the “fibre gap”. When we focus on specific types of fibre, the fibre gap is even more dramatic.  It is estimated for example that the consumption of prebiotic fibre is less than 5g per day in contrast to in excess of 100g for our prehistoric ancestors.

So the advice that we get and that we have heard for a number of years now is that we should increase our fibre intake by eating more vegetables, pulses, nuts, whole fruits and whole grains. Problem solved.

In the UK, however,  only 9% of UK adults manage to reach the target of 30g per day established in 2015 by the UK Scientific Advisory Committee on Nutrition. In the US, fibre intake among adults averages 15 g a day.

So what is preventing us from achieving the recommended daily intake of fibre? 

Well actually, it is really difficult for a number of reasons.

  1. We eat a “western” diet because we live in the modern world. We commute, we sit in front of a screen all day, we are time pressed and we don’t move our bodies much. We eat in a rush what is accessible and convenient to us. Our environment, lifestyle, daily patterns of food consumption make it very difficult to achieve the fibre levels of our ancestors. Also, calorie for calorie, refined processed foods (junk foods) are cheaper and more accessible than fibre and nutrition rich foods. 
  2. It takes a lot of plant foods to achieve high levels of fibre, for example to achieve 100g of fibre you would need 20 cups of shredded lettuce or 3lb of mixed nuts or 3.5lb of hummus.  We don’t have the time really to eat all that lettuce, and the more fibre intense plants are also more caloric. It is what you need if you are foraging around, but not if you are sitting in front of a screen.
  • Our bodies have become accustomed to the low fibre diet of the modern world and have a hard time when we try to change that. For many of us eating high levels of fibre is uncomfortable, we either feel bloated with insoluble fibres or get gas or stomach pains with soluble fibres.  Try to see what happens after you eat 3.5lb of hummus! Because of FODMAP (Fermentable Oligosaccharides, Disaccharides,Monosaccharides and Polyols) intolerance, for example, many people are cutting back on soluble “prebiotic” fibres, which is exactly the opposite of what they need.

Getting around this problem is not trivial. It requires a concerted effort to gradually change our diet to maximise fibre intake, incorporating both insoluble and soluble fibre, being careful to not to create a caloric or other imbalance. It requires planning so that each meal occasion is a “fibre” occasion and not just refuelling or eating for comfort. It requires an understanding of different types of fibres and their sources and strategies (and recipes) to facilitate incorporation into our daily routines.   

Graduality is key!

Most critically, graduality is the key. It has taken thousands of years to create the modern world and the modern human and we are going to fail if we try to change our diet too rapidly. How slow or how fast depends on the individual, where you are now and where do you want to go. If one aims to achieve the current recommended levels of at least 30g of fibre per day as the first milestone, and you are starting at the current average (US) intake of say 15g, a 2-3 month very gradual progression will be much more successful than trying to double your fibre intake overnight.

Problem solved.

Copyright © 2019 Marcelo Bravo


Reynolds et al, Carbohydrate quality and human health: a series of systematic reviews and meta-analyses, The Lancet,  January 10, 2019 (

Eaton SB, The ancestral human diet: what was it and should it be a paradigm for contemporary nutrition?, Proceedings of the Nutrition Society (2006), 65, 1–6, (

Slavin J, Fiber and Prebiotics: Mechanisms and Health Benefits, Nutrients. 2013 Apr; 5(4): 1417–1435.(

Moshfegh AJet al, Presence of inulin and oligofructose in the diets of American,  J Nutr. 1999 Jul;129(7 Suppl):1407S-11S. doi: 10.1093/jn/129.7.1407S (

Van Loo et al , On the presence of Inulin and Oligofructose as natural ingredients in the western diet,Critical Reviews in Food Science & Nutrition, (1995) 35:6, 525-552, (

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