Fibre is fashionable. On social media people talk about “fibermaxxing”, the idea of eating more and more of it. I understand the appeal, because most people do not eat enough. But the useful question is not how to eat as much as possible. It is how to eat enough, in a form your gut can handle. And you do not need grains for that.
How much fibre per day
The benchmark I give is 25 to 30 g of fibre a day. A more precise way to count is 13 to 15 g of fibre per 1,000 calories. For someone eating 2,000 calories, that comes to 25 to 30 g. An active man who eats more will need a little more, a petite woman a little less.
Health authorities say much the same. In the UK, the official guideline is 30 g a day, while most adults eat about 20 (NHS). In France, the food safety agency Anses also sets 30 g a day for adults (Cerin, based on Anses). For women the gap is often wider, with most eating 10 to 12 g a day.
The largest review on the subject, published in The Lancet in 2019, pooled 185 prospective studies and 58 clinical trials. In the observational studies, people who ate the most fibre had a 15 to 30% lower risk of death, heart disease, type 2 diabetes and bowel cancer than those who ate the least. The risk reduction was greatest between 25 and 29 g a day (Reynolds et al., 2019).
More is not always better
In a healthy gut, fibre is good for transit, the microbiome and blood sugar. In a sensitised gut, raw and highly fermentable fibre can make bloating worse instead. And too much of either type of fibre can cause diarrhoea as easily as constipation.
Athletes know this well. Before a race, 500 g of carbohydrate eaten as wholegrains would bring more than 60 g of fibre, double a normal day, with a real risk of stomach trouble during the event. That is why I talk about a useful dose rather than a record.
Soluble and insoluble, you need both
There are two main families of fibre. Soluble fibre absorbs water and forms a kind of gel, as in stewed apple or a very ripe banana. Insoluble fibre does not soak up water, like the fibre in broccoli. They do different jobs, and your gut needs both.
Fibre slows the passage of sugar into the blood and feeds the good bacteria in your gut. Foods that contain it also bring vitamins, minerals and antioxidants.
Why I do not rely on grains
Search for fibre and you almost always land on wholemeal bread, porridge oats and lentils. During The Totem Reset, I remove grains, pulses, seeds and nuts. Grains, because everyday bread, pasta and biscuits raise blood sugar fast and keep inflammation going. Pulses, because they need robust digestion and often cause excess fermentation in people who already bloat. Seeds and nuts, because today we eat them in very concentrated forms, rich in omega-6.
If people who eat more fibre, including from wholegrains, seem to do better, I think it is largely because most people constantly eat far too many processed foods that send their blood sugar soaring. Eating more fibre obviously blunts those spikes. But once you go back to eating properly, it is much less certain that you need that much fibre. So during the Reset, we remove what irritates most for 30 days and get fibre elsewhere, from foods that provide plenty of it.
Where to get fibre without grains
Vegetables first. Half the plate, with lots of colour. One vegetable or one fruit per dish is enough, and you vary the colours over the week. During the reset I prefer them steamed or roasted, courgettes, carrots, fennel, squash, spinach, beetroot. This is gentle fibre that the gut tolerates better. Big raw salads and raw cabbage come back once digestion is solid again.
Whole fruit next. All fruit is allowed, and it is one of the best sources of soluble fibre. Whole, not juiced, because juice has lost its fibre and behaves like sugar. Eat it at the end of a meal or with some protein.
Easy-to-digest carbohydrates. Sweet potatoes, potatoes, chestnuts, root vegetables. They bring fibre and the energy you need, especially around training.
Fresh herbs, rich in polyphenols, in almost everything. Chia seeds, the one seed tolerated during the reset. And fermented foods, sauerkraut, kimchi, kefir or plain yoghurt depending on your tolerance, which bring in new good bacteria. Introduce them slowly, a teaspoon to start.
If your plate falls short, a fibre supplement is a simple way to reach 25 to 30 g a day.
When you change where your fibre comes from, it is normal for transit to slow down for the first few days while your gut adjusts. Drink more, add cooked vegetables and unsweetened stewed apple, and take your magnesium in the evening. Things usually settle within one to two weeks.
What I take from it
There is no need to count every gram. If half your plate is vegetables and you eat whole fruit and tubers, you are already close to the benchmark. Start with your next meal. Your gut will tell you the rest.
This article is for information only and does not replace medical advice.