Blood Sugar Balance: Why it matters for your gut, hormones and healthy ageing

“You can only have one teaspoon of sugar in your blood at one time.”

When I was studying for my degree in Nutritional Therapy, I remember my lecturer saying this - I mean this is not exact, but it's a good visual to keep in your brain when looking at the sugar content of foods.

So what actually happens when you eat something containing a lot of sugar or rapidly digested carbohydrate?

First, let's talk about glucose.

When we eat carbohydrates, our digestive system breaks much of it down into glucose, which is absorbed into the bloodstream. Glucose is an important fuel. Your brain uses it, your muscles use it and your body needs a certain amount circulating in your blood.

The problem isn't glucose itself. It's the repeated pattern of large rises in blood glucose, followed by large insulin responses, particularly when this happens alongside a diet that's low in fibre and high in ultra processed foods.

Insulin is the hormone that helps move glucose out of the bloodstream and into cells, where it can be used for energy or stored for later use.

So what happens after a sugary breakfast?

Let's say you have a large bowl of a highly processed breakfast cereal. It's easy to eat considerably more than the recommended serving size I certainly don't know many people who carefully weigh out their 30g...

If that breakfast is relatively low in protein and fibre, the carbohydrate can be digested and absorbed relatively quickly.

Compare that with a bowl of porridge made from whole oats, topped with berries, nuts and seeds.

The carbohydrate is still there, but you've also added protein, fibre and healthy fats. This combination can slow digestion and absorption and generally results in a more gradual rise in blood glucose.

And that's really what I'm interested in when I talk about blood sugar balance.

It's not about avoiding carbohydrates, It's about looking at the whole meal.

But what about fruit?

Fruit contains naturally occurring sugars, but it's packaged very differently from a sugary drink or a highly processed food. Whole fruit comes with fibre, water, vitamins, minerals and a whole host of plant compounds. That fibre helps slow the release and absorption of its sugars.

So please don't read this as “fruit contains sugar, therefore fruit is bad.” Quite the opposite, whole fruit is an important part of a healthy, varied diet.

And if you're particularly interested in blood sugar management, pairing carbohydrate-rich foods with protein, fibre and healthy fats can be a useful strategy.

What about the dreaded blood sugar crash?

You may have experienced this yourself. You've eaten something sweet, felt great for a while and then, a couple of hours later, you're suddenly starving, tired, shaky or desperate for something sweet.

This can happen for some people following a rapid rise and subsequent fall in blood glucose, although symptoms such as shakiness, sweating and dizziness can have several possible causes and shouldn't automatically be assumed to be “low blood sugar.”

This is one reason I prefer the term blood sugar balance rather than obsessing about individual numbers.

We're looking at the pattern.

And this is where the gut comes in. A diet dominated by ultra processed foods and added sugars can also mean you're missing something incredibly important for your gut: FIBRE.

Our gut microbes thrive on a wide variety of plant fibres.

So when we replace whole foods such as vegetables, pulses, wholegrains, nuts, seeds and fruit with highly processed foods, we're not just changing the amount of sugar we're eating, we're changing the food available to our gut microbes.

And that's important because the gut microbiome is involved in far more than digestion.

It interacts with the immune system, metabolism and the gut–brain axis and produces compounds such as short-chain fatty acids when it ferments certain types of fibre.

So rather than simply asking:

“How much sugar am I eating?”

I'd rather you also ask:

“How much variety and fibre am I feeding my gut?”

And what about hormones?

This is another area where blood sugar, insulin and hormones intersect. Insulin can influence sex hormone metabolism, including the production and availability of hormones such as testosterone and oestrogen. This relationship is particularly relevant in conditions involving insulin resistance, such as PCOS.

However, it's not as simple as saying that one sugary meal causes your SHBG to fall and your oestrogen and testosterone to rise.

Hormones are influenced by insulin sensitivity, body composition, ovarian function, age, menopause, nutrition and many other factors.

So again, we're looking at the bigger picture rather than blaming one food.

So what can you actually do?

You don't need to give up carbohydrates or go low-carb.

Build meals around protein as protein helps with satiety and is particularly important for maintaining muscle as we age.

Choose high-fibre carbohydrates. Think oats, beans, lentils, wholegrains, vegetables and whole fruit.

Add healthy fats. Nuts, seeds, olive oil, avocado and oily fish can all form part of a balanced diet.

Pair your carbohydrates. Rather than eating a bowl of cereal on its own, add Greek yoghurt, nuts and seeds. Rather than fruit juice, have whole fruit alongside a meal or snack containing protein and fat.

And check your labels. You don't need to become obsessed with counting grams of sugar, but ingredient lists can be surprisingly revealing. If sugar is right at the top of the list, it's worth asking yourself how often you want that food to feature in your diet.

And finally... the Snickers advert.

I used to get REALLY frustrated by the old “You're not you when you're hungry” adverts. They're basically saying you're 'hangry' and the last thing you need is a chocolate bar as this will just make you worse! Another sugar high then and very low low...

Sometimes your body is simply asking for real food.

Preferably something that gives you protein, fibre and nutrients rather than a quick hit followed by another desperate search for the biscuit tin.

So rather than chasing your blood sugar up and down, build meals that keep you nourished and satisfied.

And if you're looking for my favourite blood-sugar-balancing breakfast?

Porridge with berries, nuts and seeds.

Simple. Delicious. Full of fibre, and should fill you up until lunchtime (if not, have some nuts and fruit for a snack)!