From Carbs to Sugar: What Your Body Really Sees

“Low sugar!” “No added sugar!” “Natural sugar only!”

This is always one of the biggest areas of confusion I have to work through with clients, and rightly so. Packets are telling us one thing, but our biology is saying another.

Food labels love to make sugar sound avoidable. But here’s the biological truth:

From the neck down, your body sees many carbohydrates -especially starchy or refined ones - as sugar. More precisely, as glucose, the molecule that enters your bloodstream and raises blood glucose levels.

That’s the sugar your body runs on. And when your glucose levels spike too high, too fast, it can leave you feeling:

• irritable or low in energy

• hungrier soon after eating

• craving more carbs

• more prone to weight gain over time, insulin resistance, and metabolic imbalance.

This is why carbohydrates need to be understood, not simply avoided or feared.

Starchy carbohydrates - compact version of glucose

Starch = Glucose in Disguise

What is starch?

Starch is a complex carbohydrate, a polysaccharide made up of long chains of glucose molecules linked together - like a train of sugar cars.

There are two main forms:

• Amylose: mostly linear chains

• Amylopectin: highly branched, digests faster

  
  

They’re found in foods like bread, rice, potatoes, and pasta

What happens when you eat starch?

1. Digestion begins in the mouth, thanks to an enzyme called salivary alpha amylase.

2. In the small intestine, pancreatic alpha-amylase takes over, chopping starch into shorter chains of just 2 units: maltose

3. The enzyme  maltase break those bonds between the 2 units in maltase to produce 2 individual glucose molecules.

4. These glucose molecules are absorbed straight into your bloodstream - raising blood glucose, aka blood sugar.

   

   
   

Bottom line: Starch simply becomes glucose, molecule for molecule. The “complex” structure doesn’t stop that, it just slows it slightly (unless it’s refined... more on that below).

What About Actual Sugar?

When people talk about sugar, they usually mean table sugar, or sucrose - a disaccharide (molecule containing 2 units) made of:

• Glucose - raises blood sugar

• Fructose - does not, but has other impacts, mainly on the liver

  
  

So while sucrose is half glucose, starch is all glucose. That means a bowl of white rice or two slices of white bread can spike your blood sugar even more than a teaspoon of table sugar.

Fun fact: We test blood glucose, not blood fructose, because glucose circulates in the blood and fuels cells. Fructose is mostly handled by the liver, which is a story for another blog.

"Low Sugar" ≠ Low Blood Sugar Impact

Here’s the trap: many processed foods boast “low sugar” but are made from refined starches - puffed rice, corn flour, potato starch.

Your body doesn't care what the label says. It cares what that food becomes. And if it becomes glucose fast, you get a blood sugar spike.

Examples:

• Rice cakes

• Cornflakes

• White wraps or crackers

• “Sugar-free” cereal bars made from rice syrup or maltodextrin

  
  

That’s why: Just because it’s low in sugar doesn’t mean it actually is once your body has digested it.

Glycaemic Index (GI) vs. Glycaemic Load (GL)

To help make sense of this, two terms are useful:

• Glycaemic Index (GI): how quickly a food raises blood sugar

• Glycaemic Load (GL): how much glucose it delivers per serving

  
  

High GI foods cause fast spikes (e.g. white bread, even faster than sugar!).Low GI foods digest more slowly (e.g. lentils, oats).

But watch out: even a low GI food can have a high GL if eaten in large quantities.

Refined Carbs vs. Whole Carbs

Refined carbs = processed carbs - starches that have been stripped of fibre, fat, protein, and micronutrients. Think white flour, white rice, or processed cereal.

Cereals, white rice, bread, pasta and flour have been refined to remove any fibre, fat and protein. These are rapidly broken down into glucose.

Because there’s no “brake system” (like fibre or fat), digestion happens fast leading to:

• Rapid glucose absorption

• Big insulin spikes

• A blood sugar crash later

  
  

Whole carbs, on the other hand (e.g. lentils, oats, sweet potatoes), still contain their fibre and nutrients. This slows digestion, blunts blood sugar spikes, and feeds the gut microbiome.

Whole carbohydrates - the unprocessed version, rich in fibre and protein. Full of goodness and great for slow release of glucose into the bloodstream.

Blood Sugar and your brain, mood, and cravings

What goes up, must come down. That post-carb blood sugar crash can trigger:

• Irritability and fatigue

• Increased hunger, especially for more quick-release carbs

• Mood dips, brain fog, even heightened PMS or anxiety in sensitive individuals

  
  

Over time, these swings contribute to:

• Weight gain, especially abdominal fat

• Insulin resistance

• Increased risk of type 2 diabetes and inflammation

Natural Sugar? It’s About the Package

You’ve heard it before: “It’s okay—it’s natural sugar.”

But again, the molecule is the molecule. Whether it came from a sugar cane or a maple tree, your body still sees sucrose.

The real difference? The food matrix.

Take an orange:

• Contains sugar, yes

• But also water, fibre, vitamin C, polyphenols, and over 100 other compounds

• These slow absorption and improve metabolic response

  
  

Now compare that to orange juice or dried fruit - more concentrated sugar, less fibre, faster spike.

Quick analogy: your body’s sugar scanner

Imagine your digestive system like a customs scanner:

• Sucrose? Scans and splits it into glucose + fructose.

• Starch? Breaks it into hundreds of glucose units.

• Fruit? Delivers a mix, but in a padded envelope full of fibre.

  
  

At the end of the day, if it becomes glucose, it hits your blood sugar—and that’s what matters for energy, cravings, and fat storage.

Key Takeaways

This blog has been about awareness - understanding the molecules in carbohydrates and how they impact our bodies in different ways. I beloieve that people deserve to have a basic understanding of food biochemistry to underpin and empower their food choices that follow. Stay with me because there will be more on tactical carb eating in future posts.

In the meantime - here are the basic bullets:

• Starch is sugar in disguise. Once digested, starch becomes glucose—molecule for molecule.

• Refined carbs can spike blood sugar even more than table sugar.

• Natural sugar isn’t harmless—only when it comes in a natural package, like whole fruit.

• Low sugar doesn’t mean low impact. Look beyond the label.

• Whole foods matter. Fibre, fat, and protein change the game.

• Blood sugar affects everyone. Not just people with diabetes.

If you would like some help in refining your diet, or even taming the effects of carbs on your blood sugar then please reach out - here to help!