I Used to Think Food Was Just Calories. Then I Discovered My Gut Microbiome.

Oct 13

8 min read

How learning about the trillions of microbes living in our gut changed the way I think about food — and four simple ways you can start supporting your gut health too.

First: I thought eating fewer calories meant making healthier choices

For years, I thought I was making healthy food choices because I was paying attention to calories.

I'd often choose the lower-calorie option without giving much thought to its nutritional value. I was far more focused on how much I was eating than on what I was actually giving my body.

Looking back, I realise how much I was missing.

Because food is so much more than calories.

It provides nutrients, fibre and a whole range of naturally occurring plant compounds that help support our health.

And one of the most fascinating things I've learned is that we're not just feeding ourselves.

We're also feeding the trillions of microorganisms living in our gut.

Then: I discovered something fascinating

I've been a huge fan of Professor Tim Spector, ZOE Science & Nutrition, and Dr Rangan Chatterjee for many years.

Their work played an important part in sparking my interest in health and nutrition, long before I decided to become a health and wellness coach.

One of the subjects that really captured my attention was the gut microbiome.

Our gut is home to trillions of microorganisms, including bacteria, collectively known as our gut microbiome.

These microorganisms help us break down certain components of food, particularly fibres that our own digestive enzymes cannot digest.

And here's the part that really changed my thinking.

What we eat can influence which microbes thrive in our gut.

Different microbes can use different types of fibre and other food components. That means the variety of foods we eat can help shape the environment in which these microorganisms live.

Suddenly, choosing food wasn't just about calorie numbers.

I started thinking about what I could add to my plate to nourish both myself and my gut microbes.

But gut health is about so much more than digestion

This was another discovery that surprised me.

Our gut microbiome doesn't simply help break down food. It also interacts with several important systems throughout the body.

Our immune system

A large proportion of our immune cells are associated with the gut.

Gut microbes and the substances they produce interact with our immune system, helping to influence how it develops and responds.

Our brain and mood

Have you heard of the gut–brain axis?

It's the two-way communication network between our digestive system and our brain.

Researchers are exploring how gut microbes may influence this communication, including possible connections with mood and mental wellbeing.

It's a fascinating area of research, although we're still learning how these findings translate into practical treatments and health outcomes.

Hormone metabolism

This is an area of research I find particularly fascinating, especially when it comes to perimenopause and menopause.

As our oestrogen and progesterone levels change during midlife, researchers are discovering that our gut microbiome may change too.

And interestingly, the relationship appears to work both ways. Certain gut bacteria are also involved in how our bodies metabolise oestrogen.

Emerging research, including studies from ZOE, has identified links between gut bacteria, diet quality and menopause symptoms.

Does this mean improving our gut health can balance our hormones or eliminate menopausal symptoms? Not necessarily. The science is still developing, and we need more research to understand what these connections mean for women's health.

But it's another fascinating reason to consider the bigger picture when supporting our health through midlife.

Inflammation

Gut microbes also interact with processes involved in inflammation.

Some produce beneficial compounds when they ferment dietary fibre, including substances called short-chain fatty acids.

These compounds play roles in gut health, including supporting the intestinal lining and interacting with immune processes.

Who knew those tiny microorganisms were involved in so much?

Fibre: it's about much more than keeping us regular

Most of us associate fibre with digestion and bowel regularity.

And while that's certainly important, fibre has other benefits too.

Some types of dietary fibre can be fermented by gut microbes, producing short-chain fatty acids such as butyrate.

Butyrate is an important energy source for cells lining the colon and helps support normal gut function.

Not all fibre behaves in the same way, which is one reason why eating a variety of plant foods is useful.

In the UK, the recommendation for adults is approximately 30g of fibre per day, yet many of us eat considerably less.

Rather than worrying about reaching that number perfectly every day, I encourage people to think about simple ways to include more fibre-rich foods in meals they already enjoy.

Wholegrains, beans, lentils, vegetables, fruit, nuts and seeds are all wonderful places to start.

If you're increasing your fibre intake, do so gradually and make sure you're drinking enough fluids.

What about eating the rainbow?

You may have heard the advice to eat a rainbow of colourful fruit and vegetables.

There's a good reason for it.

Different plant foods provide different combinations of fibre, vitamins, minerals and naturally occurring compounds called polyphenols.

Polyphenols are found in foods such as berries, colourful vegetables, herbs, spices, nuts, seeds, tea, coffee and extra virgin olive oil.

Some polyphenols are transformed by gut microbes, and researchers are investigating how these interactions may contribute to health.

This is one reason I love the idea of plant diversity.

Professor Tim Spector and the ZOE team have helped popularise the goal of eating 30 different plant foods a week.

It's a useful challenge to encourage variety, rather than a strict requirement or a magic number everyone needs to achieve.

And plant variety isn't limited to fruit and vegetables. Beans, lentils, wholegrains, nuts, seeds, herbs and spices all contribute.

Frozen and tinned options can be just as practical as fresh ones.

*More colour, more variety, more fibre-rich plants — small additions can make a difference.*

And don't forget fermented foods!

Another fascinating area to explore is fermented foods.

Foods such as live yoghurt, kefir, kimchi, sauerkraut, miso and tempeh can bring different flavours and textures to our meals.

Some fermented foods contain live microorganisms, although not all do. Whether they contain live cultures depends on how they're made and processed.

And while research into fermented foods and gut health is promising, we don't need to eat them all or buy expensive products to enjoy a varied, nutritious diet.

You could try a spoonful of kimchi alongside a meal, add plain kefir to breakfast, or experiment with tempeh in a stir-fry.

It's another opportunity to explore new foods and discover what you enjoy.

Now: I focus on what I can add

These days, my approach to food is very different.

Rather than automatically asking myself what I should cut out or eat less of, I often ask:

What could I add to make this meal more nourishing?

Could I add some lentils to a soup?

A handful of spinach to a curry?

Some extra seeds to breakfast?

A different vegetable to our evening meal?

And something else has happened along the way that I hadn't really expected.

The more I've focused on adding nourishing foods into my diet, the less I've found myself wanting the less nutritious, ultra-processed options.

When I'm enjoying meals packed with colourful vegetables, beans, wholegrains, nuts and seeds, I often feel satisfied and simply don't have the same appetite or desire for the foods I used to reach for.

It hasn't been about banning foods, counting every calorie or relying on willpower.

It's happened quite naturally as my habits and preferences have changed.

And that's probably one of the biggest lessons I've learned.

Sometimes, focusing on what we can add makes more of a difference than constantly thinking about what we should take away.

Of course, not all ultra-processed foods are nutritionally equivalent, and convenience foods can absolutely have a place in a balanced diet. For me, it's about the overall pattern of how I eat, not labelling individual foods as good or bad.

I don't eat perfectly, and I don't believe anyone needs to.

For me, it's about building small, sustainable habits that make healthy eating feel enjoyable rather than restrictive.

And one of my favourite places to start is breakfast.

My mix-it-up overnight oats

A nourishing breakfast containing fibre-rich carbohydrates, protein and healthy fats can help support a more sustained release of energy and a steadier blood sugar response.

This is one of my favourite breakfasts because it's quick to prepare, easy to vary and delicious.

*Overnight oats — a simple way to add fibre, plant variety and polyphenols to breakfast.*

Ingredients — one serving

Approximately 30g organic jumbo oats
1 teaspoon chia seeds
1 teaspoon ground flaxseed
Around 75–100ml milk of your choice, adjusting to your preferred consistency
A pinch of cinnamon, ginger or nutmeg
A small handful of chopped nuts or additional seeds
A handful of seasonal berries — frozen berries work brilliantly
Approximately 100–150g plain, authentic Greek yoghurt

How I make it

The evening before, mix the oats, chia seeds, ground flaxseed, milk and your chosen spices in a jar or bowl.
Cover and refrigerate overnight, allowing the oats and seeds to soften.
In the morning, stir the oats and add a little more milk if needed.
Top with your berries, chopped nuts and extra seeds.
Finish with a generous dollop of plain, authentic Greek yoghurt on top.

The best part is that I rarely make exactly the same combination twice!

I change the berries, nuts, seeds and spices depending on what I have available.

It's an easy way to enjoy different plant foods, fibre and polyphenols throughout the week.

And you certainly don't need expensive ingredients or complicated recipes to get started.

Four simple ways to start supporting your gut health

If all this information feels a little overwhelming, remember that you don't need to change everything at once.

Here are four realistic places to start.

1. Add a little more fibre

Try adding beans to a casserole, lentils to a soup, or seeds to your breakfast.

Start with small changes, especially if you're not used to eating much fibre.

2. Bring more colour to your plate

Add an extra vegetable to dinner or choose a mixture of berries for breakfast.

Different colours often provide different combinations of beneficial nutrients and plant compounds.

3. Mix up your plant foods

Try a different type of bean, grain, nut or vegetable each week.

You don't have to buy lots of new ingredients. Even small swaps can increase variety.

You could also experiment with fermented foods such as live yoghurt, kefir or kimchi if you enjoy them. These have been a game changer for me.

4. Remember the bigger picture

Supporting our health isn't only about food.

Regular movement, sufficient sleep, stress management and enjoyable social connections are all important parts of a healthy lifestyle.

Our gut microbiome is just one piece of a much bigger picture.

One small change can be a great place to start

If there's one thing I'd love you to take away from this article, it's this:

Healthy eating doesn't have to be about restriction. It can be about adding more nourishment, colour and variety to the foods you already enjoy.

That's certainly how my own thinking has changed.

And it's a philosophy I bring into my health coaching work, helping women build realistic habits that support their energy, confidence and long-term wellbeing.

So here's a little question to finish with:

What's one plant food you could add to a meal you already love this week?

Start there. Small changes really can add up.

Rachel x

A little more about my work

I'm Rachel Filewood, a Certified Health & Wellness Coach, supporting busy midlife women who want to feel more energised, confident and in control of their wellbeing.

My approach is realistic, compassionate and grounded in sustainable behaviour change, without restrictive rules or the pressure to be perfect.

If you'd like support making positive changes that fit into your life, you can explore my coaching services or download my free Ready for Change guide.

www.rachelfilewoodwellnesscoach.com

Home

Blog