Is Sugar Bad For You? The Truth About Carbs.

Is Sugar Bad For You?

Is Sugar Bad For You? The Truth About Carbs.

“Is sugar bad for you?” 

You’re probably expecting a straight answer.

Instead I’m going to present you some facts about sugar so you can decide for yourself.

I’ll give you my interpretation too, along with answers to some other common questions about the misunderstood carbohydrate:

  • What is the difference between rice and syrup?
  • Is white rice or brown rice better for you?
  • Why is fruit sugar different to lolly sugar?
  • Can carbs make you fat?
  • Does insulin make you fat?
  • How many carbs do you need to eat?

If you’re looking for yes and no answers, you’ve come to the wrong place.

When it comes to nutrition you need to stop seeing things as good or bad, and right or wrong. 

In most cases it depends.

Grab a coffee, I’m going to start with the facts and then address your questions. 

Ps. If you have diabetes, your situation around sugar is unique. If you want advice on your diet you need to see a registered dietician.



What are Carbohydrates?

Here’s a fun fact: the name “Carbohydrate” comes from their molecular structure.

Carbohydrates are molecules consisting of Carbon, Hydrogen and Oxygen atoms in proportions where each Carbon is “Hydrated” (has 2 Hydrogens and an Oxygen- a water molecule).

For the rest of this article I’ll be interchanging between the words carbohydrate and the shortened term “carbs” but they mean the same thing.

Carbs are not essential for the body, but they’re the preferred fuel source for your brain, nervous system and muscles to make energy.


Types of Carbohydrates and Food Sources

Is Sugar Bad For You

There are two classes of carbohydrates; Simple carbs and complex carbs.

1. Simple Carbohydrates

Simple carbs include monosaccharides and disaccharides.

Monosaccharides are one sugar molecules. You can’t break them down any further. 

The most common monosaccharides are glucose, fructose and galactose.

Fructose is found in fruit, honey and cane, beet or corn syrups.

Galactose is only found in milk and won’t be considered further in this article.

In your diet, it’s more common for glucose to occur together with another monosaccharide to form a disaccharide.

Disaccharides contain two sugar molecules attached to each other.

Lactose is mainly found in milk and is made of a glucose and a galactose unit.

Sucrose is regular sugar you’d use to bake or sweeten anything. It’s made of a glucose and fructose unit.

Maltose is formed when starches are broken down and mainly found in beer. It consists of two glucose units.

2. Complex Carbohydrates

Complex carbohydrates are chains of single sugar molecules joined together.

There are two groups of these; Oligosaccharides and polysaccharides.

Oligosaccharides are short chains of sugar molecules. You’ll find these in your diet in beans, peas, bran, whole grains and vegetables like cabbage. Certain oligosaccharides are not digested by your digestive enzymes. Instead, they get broken down by bacteria in your intestine (which is why they can make you gassy after eating them). 

Polysaccharides are long chains of up to thousands of sugar units joined together. The main polysaccharides in your diet are starch and cellulose. Glycogen is another polysaccharide and it’s the main storage form of carbohydrate in your body.

Starch is found in your diet in potatoes, legumes, vegetables and cereal grains. Cellulose is basically fibre. Your digestive enzymes can’t absorb it and it’s mainly a bulking agent.


Digestion of Carbohydrates

Most of the carbohydrates you eat are in the form of:

  • disaccharides= simple carbs = what you’d consider as “sugar” or sugary foods like lollies and cake
  • polysaccharides = complex carbs = what you’d consider as starchy carbs like bread and pasta

These are too big to get into your cells.

They first need to be broken down into their basic components – glucose or fructose- so they can be absorbed into the bloodstream and transported into your cells.

Your body breaks down simple carbs more quickly because there are less sugar units joined together to be broken down.

Starchy carbs get digested in your mouth and in your small intestine. The end products are individual glucose molecules. 

“Sugar” is digested in your small intestine only. Different enzymes are needed to break down each disaccharide. The enzyme that breaks down lactose diminishes in some people which is why you might become lactose intolerant. The enzymes that break down maltose and sucrose don’t work on lactose. The end product of most of the “sugar” you eat will be a glucose and fructose molecule. 


Absorption and Transport of Carbohydrates 

This is where things get interesting and complicated.

The end result of digestion is going to be glucose or fructose molecules.

Your body handles the absorption of glucose and fructose differently.

Glucose mostly gets absorbed into your circulation, goes to your liver and then to other organs. Pretty much every cell in your body can use glucose for energy, whereas only your liver can break down fructose.

Fructose is transported to the liver where it’s kept and turned into energy or other precursor molecules. These molecules can lead to the production of fat, but it DOES NOT mean fructose makes you fat.

If someone tells you fruit makes you fat, they’ve probably misunderstood the metabolic pathways of fructose in the liver. What happens to fructose in the liver is complicated and the research around it is still evolving.

The absorption of fructose is slower than glucose. If you don’t consume it with matching amounts of glucose (like it would be in table sugar), it can cause an upset stomach if you have an issue known as fructose malabsorption. 

One last difference between fructose and glucose is that fructose doesn’t spike your blood glucose levels to the same extent that glucose does.


Regulation of Blood Glucose

Glucose is one of the most important molecules in your body. Most cells need a continuous supply of it in order to make energy. The levels in your blood go up and down when you eat, which is why you need the hormones, insulin and glucagon. 

They act in an antagonistic way to control blood glucose concentrations. Your liver plays a major role too, as it is where a number of metabolic reactions take place to either return glucose to the blood or remove it.

High blood glucose= pancreas releases more insulin and less glucagon

Insulin acts to reduce blood glucose levels. It shuttles glucose into cells, increases the synthesis of glycogen in the liver and fatty acids in adipose tissue. This is a dynamic process. The opposite occurs when blood glucose is too low.

Your body is always trying to maintain your blood glucose concentration within a precise range. It does this fine on it’s own, unless you have a disease like diabetes.

Type 1 diabetes is where the pancreas stops producing insulin.

In Type 2 diabetes, cells stop responding to insulin. Obesity has been linked to the development of insulin resistance and diabetes. It’s actually not known for sure whether it’s weight gain that leads to insulin resistance and then diabetes OR if insulin resistance leads to weight gain and then diabetes. Regardless, losing weight can help improve your insulin sensitivity. As you lose weight, your body seems to be better able to handle carbohydrates. 


The Glycemic Index

One last way of classifying a carbohydrate is based on its glycemic index. 

Certain carbs are digested and absorbed from your intestines more quickly than others. This influences how quickly your blood glucose levels rise.

The glycemic index is a way of quantifying the effect of carbohydrate containing foods on your blood glucose levels.

Foods that cause a rapid rise and fall in blood glucose levels have a high GI. Foods that cause a slower rise and more gradual fall have a lower GI- these tend to keep you fuller for longer.

Knowing the glycemic index of a food isn’t that useful.

You hardly ever eat a single food on it’s own.

When you eat a bowl of rice, you usually have it as part of a meal. The other components of the meal will influence the digestion and absorption of the rice. For example, cooking the rice in oil will add fat to the meal which will slow down the absorption and how quickly it causes your blood glucose levels to rise.

As long as you’re eating a balanced diet and are not diabetic, you don’t really need to worry about the glycemic index of carbohydrates. An exception to this is when it comes to what you eat around your workouts.


Is Sugar Bad For You

Pre and Post Workout Carbs

Before your workout it can be helpful to eat some carbs that have a low to moderate glycemic index, like a banana, because it won’t result in a quick rise and fall of your blood glucose levels.  

After your workout you want to replenish your glycogen stores and deliver amino acids to your muscles as quickly as possible. That’s why you might have heard that you should limit fat in your post-workout meal. It slows down the digestion and absorption of your food. Ideally your post workout meal should consist of some low fat protein, like chicken breast, and a higher GI carb, like white rice.

Overall, meal timing is not crucial for either fat loss or muscle gain. There are much more important things to get right first outlined in this.




What is the difference between rice and syrup?

Your body breaks down starches like rice into glucose and this happens slowly. It breaks down syrup into a combination of glucose and fructose more quickly.

If fat loss is your goal, there’s no reason to avoid either. Rice may be something you want to include more of since it’s going to keep you fuller for longer. If you had 100 calories of rice and 100 calories of syrup, you’ll get more food volume if you choose the rice which is also beneficial for fat loss (helps you feel less deprived when eating in a calorie deficit).


Is white rice or brown rice better for you?

It depends. They’ll both become glucose once broken down.

The main difference between white rice and brown rice is the fact that white rice has had some of the nutrients and fibre removed. You digest white rice slightly more quickly than brown rice.

Brown rice has anti-nutrients which may prevent the absorption of some nutrients from your food. It’s also more difficult to digest. So it isn’t as simple as saying one is better than the other. Eat whatever makes you feel better and fits within your calorie requirements for your goals.


Why is fruit sugar different from lolly sugar?

Depending on the type of sugar used to make the lollies, fruit sugar and lolly sugar could be very similar once broken down by the body. Both are simple carbs at the end of the day.

What makes fruit different to lollies is the fact that fruit also contains a bunch of micronutrients as well as fibre. Fruit is “healthier” than lollies because of this. It has nothing to do with the type of sugar.

Fruit might be a better option for fat loss because it will help keep you full (thanks to the fibre) and you’ll be able to eat a lot more of it for the same amount of calories.

As long as you’re getting enough micronutrients in your diet, and sticking within your calorie requirements, you can eat some lollies, be healthy and lose fat. You can learn more about micronutrients here. 


What about natural sugar like agave syrup?

Different “sugars” contain different ratios of glucose and fructose.

Natural sugar is still sugar!

What makes agave syrup ok in some cases for diabetics, for example, is the fact it’s mostly fructose. Fructose doesn’t spike blood sugar like glucose does. If you have fructose absorption issues then agave syrup might not be the best option for you.


Can carbs make you fat?

If you eat too many of them then yes. But it’s not because of the carbs. It’s because you’re eating too much food overall.

Carbs provide energy to your entire body, especially your brain and muscles. They do not make you fat. Eating too many calories is what makes you fat.


Is sugar bad for you?

This depends!

How much sugar are you consuming and what is the rest of your diet like?

High fructose diets have been associated with fatty liver disease and metabolic diseases. But you have to be eating a high fructose diet (from things like sugary drinks and lots of food containing high fructose corn syrup) for months for this to happen.

Having some ice cream for dessert every day is not a high fructose (or even high sugar) diet.

Eating a diet consisting of mostly sugar, and eating a diet consisting of mostly whole foods with some treats each day, are two different things.

When it comes to your diet, you need to use your common sense.

It doesn’t make sense to completely restrict sugar. You create a need to binge and you’re probably not going to be able to do it consistently. If you do, you’ll miss out on some of the social aspects of food, like enjoying cake with your kid at their birthday party.  There’s no conclusive evidence to show sugar causes harm if eaten in moderation.


Does insulin make you fat?

No. Insulin is a storage hormone not a fat producing one.

In addition to the role it plays in maintaining your blood glucose levels, it’s also important for protein synthesis and muscle growth. It does inhibit enzymes involved in the breakdown of fatty acids, but it also inhibits enzymes involved in the breakdown of glycogen and amino acids (so you can build muscle).

Insulin does not make you fat. Too much food makes you fat.


How many carbs do you need to eat?

It depends on your goal, where you’re at now and your activity levels.

Check out this article to work out how many carbs you need for you.


Do carbs really help you sleep?

Eating carbohydrates before bed can help increase tryptophan in the brain. This increases the production of serotonin which goes on to make melatonin. Melatonin is a hormone which helps to induce sleep.

So yes, carbs can help you sleep.

If you’re worried about gaining fat if you eat carbs after 6pm, don’t be. That’s a myth. You can eat any food, at any time of the day, and still lose fat so long as you’re in a calorie deficit.

The effect of carbohydrates on the tryptophan- serotonin pathway in the brain is also why they can impact your mood. But that’s opening up a long rabbit hole and it’s time to finish this article.


A final note…

Be careful of misleading advice around sugar, and any food. Compared to physics and chemistry, nutrition science is very young. Scientific studies on individual nutrients and foods are incredibly difficult to conduct to get meaningful results. 

What is known for sure is that calories matter most whether your goal is fat loss or muscle gain. That’s physics.

And for now, there’s no need to be scared of sugar or carbohydrates. 

If you have any more questions about carbs or your diet and fitness goals, you can contact me here. 


Further Reading:

International Tables Of Glycemic Index

Advanced Nutrition and Human Metabolism 

Pathways and Mechanisms Linking Dietary Components to Cardiometabolic Disease

History of Modern Nutrition Science