Fibre: One of My Biggest Lessons in Nutrition

Tim Gears · Founder & lead coach, Pillars Nutrition

One of my biggest learning outcomes over the last couple of years has been fibre.

With my background in training, you might expect me to say protein. And protein absolutely deserves attention. But fibre is the subject that has made me stop, learn more and think harder about what a good day of eating actually looks like.

The more I understand it, the more I want to help people give it a regular place in their meals. If you’re wondering how to eat more fibre, this is where I would start.

Working one-to-one with clients has shown me how easily fibre gets overlooked. People often know they need protein, but have much less idea where fibre comes from or how much they eat.

What actually is fibre?

Fibre is a type of carbohydrate found in plant foods that our digestive enzymes cannot break down in the small intestine. You’ll find it in oats, beans, lentils, fruit, vegetables, nuts, seeds and wholegrains.

It reaches the large bowel, where some types help bulk up our stools and others are broken down by gut bacteria. Different fibres do different jobs. That is why eating a variety of these foods makes sense.

For everyday life, the useful bit is this: fibre can support regular bowel movements, and some types help with cholesterol and the rise in blood sugar after meals. Fibre-rich meals can also help us feel satisfied. The effect depends on the food, the amount and the person.

Why this matters when you’re hungry all the time

If you finish a meal and spend the next two hours thinking about food, simply being told to “eat less” is not much help.

I want to look at the meal with you. Was there enough food? A source of protein? Some fibre? Did you actually enjoy it? A bowl of oats with berries, or a jacket potato with beans, gives us something useful to work with.

Fibre can make managing appetite easier, but it doesn’t guarantee fullness or cause fat loss by itself. For fat loss, we still need to take in less energy than we use over time. The coaching is in finding a way to do that which you can live with.

Read more: fibre and blood sugar

Some fibres form a gel during digestion and can slow how quickly carbohydrate is absorbed. That can soften the rise in blood glucose after a meal. The portion and the rest of the meal matter too.

A rise in blood glucose after eating is normal. Feeling tired or hungry later does not, on its own, tell us you have had a blood sugar “crash”. Sleep, stress and how much you have eaten also deserve attention.

Read more: what does TEF mean?

TEF means the thermic effect of food: the energy your body uses to digest, absorb and process what you eat.

Protein generally takes the most energy to process: roughly 20–30% of its energy content, compared with about 5–10% for carbohydrate and 0–3% for fat. These are research estimates, not a calculation to subtract from each meal.

Fibre affects digestion and how much energy we absorb, but that does not mean every high-fibre meal burns lots of extra calories. I would focus on comfortable digestion, satisfying meals and consistency rather than trying to earn a calorie discount.

Your gut bacteria need feeding too

Your gut is home to a community of microbes, often called the gut microbiome. Some bacteria use fibre as food. In the process, they make substances called short-chain fatty acids, which help support the gut lining.

You don’t need to memorise those names. Think variety across the week: oats one morning, lentils in a soup, beans with dinner, different fruit and vegetables when you can.

Read more: do I need 30 different plants a week?

I like “30 plants a week” as a prompt to try more variety. The idea draws on observational research linking a greater variety of plants with a more diverse gut microbiome. It is not a proven pass-or-fail target.

Fruit, vegetables, beans, lentils, wholegrains, nuts and seeds all offer options. Herbs and spices add variety too, but a pinch of seasoning won’t provide the fibre of a portion of beans. Start by adding one different plant food to your usual week.

And where do fermented foods fit?

Yoghurt, kefir, kimchi and sauerkraut are examples of fermented foods. They can be enjoyable additions to meals, alongside the foods that provide fibre.

For example, yoghurt or kefir with berries and oats brings the two together. The berries and oats supply the fibre; plain dairy yoghurt and kefir do not. You don’t need to buy every fermented product on the shelf.

Read more: what does the research say?

In a small trial in healthy adults, a diet rich in fermented foods increased gut microbial diversity and reduced some markers of inflammation. That is encouraging, but it does not show that every fermented food has the same effect or that it will treat a health condition.

Not all fermented foods still contain live microbes when eaten, and “fermented” does not automatically mean “probiotic”. Choose something you enjoy and tolerate.

Think about meals you can repeat

In Pillars, I’ve described this as moving from “level one” to “level two” thinking. In plain English, it means moving beyond “Can I eat bread?” or “Are carbs bad?” and asking: “What meal will work for me on a busy Tuesday?”

That might mean keeping oats and frozen berries ready for breakfast, adding a tin of beans to a chilli, or having soup in the freezer for lunch. Learning the science should make your next meal easier to put together.

How to eat more fibre: three chances each day

This is the idea I keep coming back to. Look across the day and give fibre a few regular opportunities, so you aren’t trying to squeeze the whole lot into dinner.

Breakfast, lunch and your evening meal are an easy place to look. If your routine is different, work with that. There is no need to start eating breakfast or add snacks just to follow a formula.

You don’t have to change all three meals tomorrow. Choose the easiest one first. Nor do three additions automatically add up to your daily fibre target: the foods, portions and the rest of your day still matter.

What does 30g mean for you?

The UK recommendation for adults is 30g of fibre a day. That is useful to know, but it doesn’t tell me what you should change tomorrow. I need to understand where you are starting from.

If you currently eat very little fibre, asking you to jump straight to 30g may be uncomfortable and difficult to keep up. I would much rather help you make one change, see how it feels and build from there.

If you already use Cronometer, look across several properly logged days. That can help you spot which meals offer an opportunity. If you don’t track your food, start by looking at the foods on your plate. You can make a useful change without downloading an app.

Your digestion needs a say

Increasing fibre quickly can cause gas and bloating. Add it gradually, drink regularly and notice how you feel.

If a particular food keeps causing discomfort, we can look at the amount, preparation or a different option. Eating something through pain simply to reach a number makes no sense to me.

A bowel condition, previous bowel surgery or a prescribed low-fibre diet can change the advice. Speak with your clinician or dietitian before increasing fibre in those circumstances. Significant or persistent digestive symptoms also deserve individual advice.

What about “fibremaxxing”?

You may have heard this word for deliberately eating more fibre. If it encourages you to try oats, beans or a different vegetable, useful. There is no need to chase the highest number or make yourself uncomfortable.

What I’ve noticed myself

Since giving fibre more attention and eating a wider range of plant foods, I’ve noticed better fullness, more comfortable digestion and less time thinking about food. That is my experience of changing my overall way of eating; it isn’t a promise that fibre alone will do the same for everyone.

I invest in continuing education because I want Pillars to give you more than another list of nutrition rules. The useful part is taking what we learn and making it work around your job, your family and the weeks when life is difficult.

Start with one meal. Where could you give fibre a little more room?

Tim Gears
Founder & lead coach, Pillars Nutrition

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Sources and further reading

Adapted from my Pillars article “Fibre: The Missing Piece in Modern Nutrition” and the Pillars Fibre Action Plan. Personal experiences are described as such; the sources below support the wider explanations.

NHS: How to get more fibre into your diet — the UK adult recommendation and food ideas.

St George’s NHS: Dietary Fibre — different fibres and their roles in digestion.

Westerterp: Diet induced thermogenesis — the energy used to process food.

Koh and colleagues: From Dietary Fiber to Host Physiology — fibre fermentation and short-chain fatty acids.

Wastyk and colleagues: Gut-microbiota-targeted diets modulate human immune status — the small fermented-food trial.

McDonald and colleagues: American Gut — observational research on plant variety and gut microbes.