How much fibre per day you need and how to reach 25 g

On social media they call it fibermaxxing: pushing fibre as high as possible with oats, chia, legumes and vegetables. Google listed it among the trends of summer 2026 and the press has been writing about it since July. Like almost every wellness fad, it starts from a real fact —we eat too little fibre— and takes it to an extreme nobody needs.

The reference figure in Europe is 25 grams a day. It is not a maximum and it is not a performance target: it is the amount at which the gut works normally. Here is how much fibre you really need, where to get it from your weekly shop, and why going past 50 grams a day does you no favours.

In short

• 25 g a day is the adequate intake set by EFSA for adults, and the criterion used to calculate it is normal bowel function, not disease prevention.
• In Spain, estimates range from 12-13 g/day in some datasets to an average of 22 g/day in others, with big differences between regions: 16 g in the Canary Islands versus 25 g in the Valencia region.
• The largest meta-analysis available (185 studies, 58 trials) places the benefit at 25-29 g/day: every extra 8 g a day is associated with a 5-27% lower risk of all-cause mortality, coronary heart disease, type 2 diabetes and colorectal cancer.
• A single plate of cooked lentils (198 g) provides 15.5 g of fibre: 62% of the daily target. It is the cheapest lever there is.
• Fibermaxxing overshoots: sustained intakes above 50-60 g a day interfere with the absorption of iron, calcium and zinc, and raising fibre suddenly causes gas and bloating.
• Fibre from whole foods is not interchangeable with fibre from a tub. Supplements have specific uses; they are not a shortcut to skip vegetables.

Why the figure is 25 grams and not 40

In 2010 the European Food Safety Authority set the adequate intake of dietary fibre at 25 g/day for adults, and it did so using a very specific criterion: bowel function. In its own words, the role of dietary fibre in bowel function was considered the most suitable criterion for establishing an adequate intake. For children from one year of age the reference is 2 g per megajoule of energy consumed, in other words proportional to how much the child eats.

That explains why the figure looks low compared with what you read online. 25 g is the "this works fine" threshold, not the ceiling of the benefit. When you look at long-term health, the curve keeps rising: the series of systematic reviews and meta-analyses published in The Lancet in 2019 —185 observational studies with 135 million person-years and 58 clinical trials with 4,635 participants— found the best risk profile in the range of 25 to 29 g/day, with reductions of 5 to 27% in all-cause mortality, coronary heart disease, type 2 diabetes and colorectal cancer for every additional 8 g a day. For whole grains, every extra 15 g a day was associated with reductions of 2 to 19%.

Two caveats that are rarely mentioned. First: these are observational studies, and people who eat a lot of fibre tend to eat more vegetables, more legumes and fewer ultra-processed foods, so part of the effect comes from the whole diet rather than the isolated nutrient. Second: the authors suggest that intakes above 29 g might offer a little more protection, but they do not quantify how far up. Going from "there might be something more above" to "the more, the better" is a leap the evidence does not make.

What fibermaxxing is and where it goes wrong

Fibermaxxing means deliberately maximising daily fibre, usually well above the recommendations. The good part is that it pushes people towards foods they should eat more of: legumes, vegetables, fruit, whole grains, nuts and seeds. The bad part comes down to three specific things.

One: more is not better indefinitely. Specialists put the point at which fibre starts to interfere with mineral absorption —iron, calcium and zinc in particular— at around 50-60 g a day sustained. It is not a poison, it is an opportunity cost: you fill your plate with something that drags out nutrients you do need.

Two: speed matters more than the number. Going from 12 to 35 g in one week causes gas, bloating and cramps, because the gut microbiota suddenly ferments a substrate it is not used to. The advice is unanimous: increase gradually —2-3 g more each week— and drink more water with it. Without enough fluid, insoluble fibre makes constipation worse instead of fixing it.

Three: supplements do not replace food. A tub of fibre powder provides one specific type of fibre. A plate of lentils provides soluble and insoluble fibre, resistant starch, protein, iron, folate and potassium. If the goal is your microbiota, what matters is the variety of plant fibres, not the total grams of a single one.

Five levers to reach 25 g without obsessing

1. A plate of legumes three times a week

This is by far the lever with the best effort-to-result ratio: 200 g of cooked lentils provide 15.5 g of fibre, 62% of the daily target in a single plate. Black beans are almost the same (15 g per 170 g cooked) and peas come in at 9 g per serving. If you buy dried legumes, it is cheaper and you control the cooking; if you are short of time, canned legumes and frozen ones have the same fibre as those cooked at home.

2. Swap refined for wholegrain, without a second thought

This change does not require cooking differently or eating more: it is the same meal with a different product in the cupboard. A plate of cooked wholewheat spaghetti provides 6 g of fibre versus just over 2 g for white pasta. The same goes for rice and bread. Start with pasta, rice, flours and bread from the bakery, and review the cereals and grains you already have at home.

3. Two tablespoons of seeds a day

It is the fastest way to add fibre without changing your menu. 28 g of chia seeds provide 10 g of fibre, and ground flaxseed is around 27 g per 100 g. They go into yoghurt, porridge, salads or bread dough. In seeds you will find bulk chia and brown flaxseed. Flaxseed needs to be ground or bought ground: whole seeds pass through unopened and do not deliver what the label says.

4. Oats for breakfast

A cup of cooked oats has 4 g of fibre, and much of it is beta-glucan, the soluble fibre with an authorised EU health claim: "Beta-glucans contribute to the maintenance of normal blood cholesterol levels", based on a daily intake of 3 g of beta-glucans from oats or barley. It is one of the few statements about fibre that European law allows to be made in those words. In cereals, bars and muesli you will find bulk oat flakes and the wholegrain oat flakes from our own brand in a one-kilo pack.

5. Fruit with the skin on and vegetables at both main meals

An apple with its skin has 4.5 g and a medium pear 5.5 g; peeling them removes a good part of that. Raspberries are the extreme case among fruits: 8 g per 120 g. As for vegetables, cooked broccoli provides 5 g per cup. If the problem is planning rather than willpower, organic boxes sort out the week's fruit and vegetables in one go.

How much fibre each serving really has

The data come from the Mayo Clinic high-fibre foods chart, based on the USDA food composition database. They are in grams per real serving, not per 100 g, because that is what you actually eat.

A normal day goes past 25 g without forcing anything

No green smoothies, no supplements. And with the point that comes up most often in practice: take the plate of legumes out of this day and the total collapses.

Two takeaways. First: you do not need to force anything to pass 25 g, so fibermaxxing solves a problem that a different shopping list fixes. Second: the plate of legumes is a third of the day's fibre. If you only change one thing in your shopping this week, change that.

The shopping list

Everything that raises your weekly fibre, aisle by aisle:

• The basics: dried and jarred legumes, wholegrain cereals and grains, brown rice and wholewheat pasta.
• Breakfast: oat flakes, muesli and bars, wholemeal bread and wholemeal flours for home baking.
• Add-ons: chia, flax, hemp and sunflower seeds, and skin-on nuts.
• Fresh: vegetables, seasonal fruit, berries and weekly organic boxes.
• So you don't have to cook every day: frozen vegetables and legumes, canned goods and compotes with no added sugar.
• Fermented foods, which work alongside fibre: yoghurt and kefir and chilled fermented foods such as kimchi and sauerkraut.
• If you are going to supplement: digestive system, digestive enzymes and probiotics and superfoods.

Do you need fibre supplements?

To reach 25 g, no. With a plate of legumes, two tablespoons of seeds and fruit with the skin on, the number takes care of itself, and whole food provides things powder does not. That said, there are three situations where a supplement makes sense, and they are worth naming:

Constipation that diet does not fix. Psyllium husk (Plantago ovata) is a gel-forming soluble fibre and the option with the longest clinical track record for regulating bowel movements. Take it with a large glass of water; without fluid, it makes things worse. We also stock bulk psyllium so you can try 100 g before buying a kilo.

Slightly high cholesterol, with room to act through diet. Here the fibre with an authorised EU claim is not psyllium but beta-glucan: 3 g a day of beta-glucans from oats or barley. That is roughly 60-80 g of oat flakes a day. You can get there by eating, and it is much cheaper.

Very restrictive diets. A poorly planned gluten-free diet, a very low-carb diet or one with little plant variety. There, fibre is genuinely lacking and a supplement plugs the gap while the underlying problem is corrected.

And one situation where a supplement is exactly the opposite of what you need: if you have bloating and gas, raising fibre suddenly makes things worse. With irritable bowel syndrome or suspected bacterial overgrowth, more fermentable fibre means more symptoms. That is something to look at with a professional, not with a tub. We cover it in more detail in our post on the gut reset and the microbiota.

Where to buy bulk fibre in Barcelona and Sant Cugat

The advantage of buying loose here is concrete: fibre is the first thing people give up on when they buy a kilo of something they are not sure they will tolerate. With 100 g of psyllium or 200 g of chia you try it for a week and decide. In our three shops we sell loose fine and jumbo oat flakes, chia, flaxseed, sunflower seeds, dried legumes and psyllium powder, and you can ask at the counter which fibre suits you —soluble and insoluble are not the same if the problem is constipation or if it is bloating—.

• Linverd Provença — Provença 242, 08008 Barcelona (Eixample, between Balmes and Enric Granados).
• Linverd Còrsega — Còrsega 78, 08029 Barcelona (Eixample, near Sants station).
• Linverd Sant Cugat — Antoni Bell 2, 08174 Sant Cugat del Vallès (Volpelleres neighbourhood).

Phone: +34 683 118 961. Email: linverd@linverd.com. If you would rather not go out, the full pantry range is in the online shop and we deliver to homes in Barcelona and the surrounding area.

Frequently asked questions

How much fibre should you eat per day?

EFSA sets the adequate intake at 25 g a day for adults, calculated on the basis of normal bowel function. Long-term health studies place the best range at 25-29 g a day. For children over one year old, the reference is 2 g of fibre per megajoule of energy consumed.

What is fibermaxxing and is it safe?

It is the trend of pushing fibre intake well above the recommendations. The direction is right, because most people eat less than 25 g, but the extreme adds nothing: sustained intakes above 50-60 g a day interfere with the absorption of iron, calcium and zinc, and increasing suddenly causes gas and bloating. The sensible approach is to add 2-3 g a week and drink more water.

How much fibre is in chia seeds?

About 10 g of fibre per 28 g of seeds, so two tablespoons cover more than a third of the daily target. It is the fastest way to add fibre without changing your menu, but it is best introduced gradually and with liquid, because chia forms a gel.

Does fibre cause bloating?

A sudden increase does: the microbiota ferments the new substrate and produces gas. It usually settles within two or three weeks if you increase gradually. If bloating persists or appears with small amounts, there may be irritable bowel syndrome or bacterial overgrowth behind it, and then more fibre is not the answer.

Soluble or insoluble fibre?

Soluble fibre (oats, legumes, psyllium, apples) forms a gel, feeds the microbiota and helps with cholesterol and blood sugar. Insoluble fibre (bran, fruit skins, leafy greens, nuts) adds bulk and speeds up transit. A varied diet provides both; problems usually come from eating only one.

Does psyllium work for constipation?

It is the supplemental fibre with the longest track record for regulating bowel movements, and it works by forming a gel that adds bulk and softens stools. Two conditions: always take it with a large glass of water, and start with one teaspoon, not the dose on the pack.

Where can I buy bulk oats, chia or psyllium in Barcelona?

In the three Linverd Market shops: Provença 242 (08008 Barcelona), Còrsega 78 (08029 Barcelona) and Antoni Bell 2 (08174 Sant Cugat del Vallès). We sell loose oat flakes, chia, flaxseed, dried legumes and psyllium powder, from 100 g. Phone +34 683 118 961.

The takeaway

Fibre is the nutrient most people fall short on and the easiest one to fix without buying anything exotic: legumes, wholegrain instead of refined, seeds, and fruit with the skin on. Start with the plate of legumes and raise the rest slowly. You will find the whole organic pantry in the online shop, and legumes and whole grains do 70% of the work. If you would rather see it and ask, we are at Provença 242 and Còrsega 78 in Barcelona and at Antoni Bell 2 in Sant Cugat.

If the topic interests you, keep reading: Back to routine: how to reset your digestion after summer —and remember to drink enough, because without water fibre cannot do its job—. And the whole health blog.

This information is for general guidance and does not replace advice from a healthcare professional. If you have a diagnosed digestive condition, take medication or are pregnant, ask before changing your fibre intake or starting a supplement.