Woman adding teaspoon of sugar to her coffee

10 Reasons Why Sugar is Bad For You

From pasta sauces to peanut butter, sugar can be found lurking everywhere. Learn more about where sugar hides.

Australians consume an average of 14 teaspoons of sugar a day, Americans 31. The WHO recommended daily allowance is 5 to 10 teaspoons.

Since we live busy lives and end up taking shortcuts like eating ready meals and packaged snacks, most of us inadvertently end up consuming way more sugar than we realize.  What makes it even tricker is that the food industry has very cleverly come up with many new names for sugar so that even if you are looking at the food labels to check how much sugar is in what you’re buying, you’ll likely end up being hoodwinked.

What’s the problem with sugar, you might ask? Here are 10 reasons why eating too much is bad for you.

1. Makes you fat

Sugary foods are high calorie foods. And unless you’re going to be using up those extra calories you’ve consumed with some energy requiring activity, your body will store the surplus as fat. Typically, this is fat that’s laid down around your belly. Sugar is why your waistline is not where you want it to be. Additionally, excessive sugar, especially fructose – the main type of sugar in starchy foods – interferes with the production of leptin, a hormone produced by fat cells which tells your brain that you are full and should stop eating. Ever noticed how some foods you can just eat and eat and eat?

2. Makes you look older

Too much sugar prematurely ages your skin. Excess sugar in the bloodstream ends up binding to proteins and fats to create complexes called advanced glycation end products (AGEs). AGEs accelerate the ageing process. Think of them as the opposite of anti-oxidants. AGEs cause tissue damage and inflammation. In the skin they cause loss of flexibility resulting in skin sagging and wrinkling. 

3. Increases your risk of diabetes

Obesity is the single greatest risk factor for developing diabetes and sugar is the major driver of weight gain and obesity. Insulin is a hormone produced by the pancreas to regulate the amount of sugar (glucose) in the blood. We get glucose from carbohydrates that are broken down into glucose during digestion. Examples of carbohydrates include grains, fruits, vegetables, dairy products, lollies, chocolate, cakes, biscuits and soft drinks.

Whenever we consume these types of food and drink, as they are digested sugar is released into the blood. The pancreas literally tastes the sweetness of the blood and starts secreting insulin, whose role is to grab glucose out of the bloodstream and put it into our cells to use as fuel. This way the blood sugar level should always remain nice and steady.

Obesity causes disruption of this mechanism as fat starts getting stored in places where it shouldn’t be, such as in the pancreas and liver as well as in your muscles. The added fat stifles the signals that insulin sends out to these tissues. This is what is known as insulin resistance. As a result glucose isn’t shifted out of your blood as effectively and keeps circulating around your body rather than being used for energy by your cells. When blood sugar levels reach a certain level, a diagnosis of diabetes is given.

4. Increases your risk of heart disease

After the US government decided to wage a war on fat in the 1960s, while we were all focusing our energy on avoiding fat, sugar crept into over two thirds of the packaged foods and drinks that we consume. And while the low-fat revolution did nothing to help reduce the heart disease it was meant to tackle, it is culpable for the astronomical rise in diabetes around the world. And since people with diabetes are 2 to 4 times more likely than others to develop heart disease, the low-fat movement has inadvertently caused even more heart disease.

5. Increases aches and pains

Too much sugar causes the body to produce cytokines which are proteins that initiate the body’s inflammatory response. Over time the inflammation triggered by high cytokine levels causes pain, swelling and stiffness in the joints. This same process of cytokine release can also cause inflammation of the muscles resulting in a body that just seems to ache all the time.

6. Decreases fertility

Too much sugar can affect fertility in two main ways. Firstly, the inflammation caused by sugar through the production of AGES and cytokines can drive inflammatory conditions like endometriosis which is responsible for 35 to 50% of female infertility cases.

Secondly, excess sugar causes weight gain and insulin resistance leading to polycystic ovarian syndrome (PCOS) which is one of the leading causes of female infertility worldwide.

Woman checking pregnancy test

7. Affects mental health

Let’s face it, we’ve all had the sugar highs and the sugar lows. And now there is evidence that excessive sugar consumption is linked to the development of depression. A 2015 study of nearly 70,000 women demonstrated that those with the highest intakes of added sugars had a significantly increased risk of depression. 

8. Speeds up ageing in your body

AGEs affect the elasticity of blood vessels. This can happen in larger blood vessels such as the coronary vessels, increasing the risk of angina and heart attacks. People with diabetes are 2 to 4 times more likely to develop cardiovascular disease. In the brain the effects of AGEs can cause strokes. AGEs can also cause damage in the smaller vessels in the body such as the capillaries in the kidneys, resulting in kidney damage that over time can progress to full blown kidney failure. In the eyes capillary damage from AGEs can cause deterioration in vision. AGEs can also cause neuropathy, a disorder of the nerves leading to abnormal sensations such as pins and needles, burning and even increased pain especially in the hands and feet.

9. Damages your liver

Excess sugar that’s not used for energy gets stored in the liver as a protein called glycogen. When the liver has enough glycogen inside it but the sugar keeps on coming, it starts getting stored as fat. The liver should look like a nice lean sirloin steak. After sugar has had its way with the liver, it starts looking more like a rib eye steak, streaked with fat. This is called fatty liver and can cause the same kind of inflammation in your liver as alcohol does. About 10% of people with fatty liver from eating too much sugar can go on to develop irreversible liver scarring called cirrhosis. 3% of people with cirrhosis will develop liver cancer.

10. Affects your brain

Eating sugar triggers the pleasure-reward circuit in the brain by activating the release of dopamine. Dopamine makes us feel good, really good. It’s the same neurotransmitter released when people use cocaine, heroine, methamphetamine. This pleasure reward circuit is responsible for creating cravings to consume more of the substance that triggered the dopamine surge. The more sugar you eat, the more sugar you will want to eat.

In addition to the increased risk of mood disturbances and stroke caused by a high sugar diet, sugar causes inflammatory changes in the hippocampus that can to lead memory impairment. AGEs are associated with increased amyloidosis, the build-up of proteins in the brain which are associated with Alzheimer’s disease. In the US 1 in 9 people over the age of 65 has Alzheimer’s. 

Sugar has invaded our supermarket shelves, our pantries and our kids’ lunchboxes, and it’s become really hard for most people to stick to the WHO daily recommendations. So much so, that even the WHO had to loosen their initial recommendation of less than 6 teaspoons a day, to between 5 and 10 teaspoons daily. Sugar is the bad guy, fuelling the global obesity and type 2 diabetes crises along with increased heart disease, kidney disease, blindness and dementia. 

Although technically sugar is not classified as an addictive substance, it could be argued that it ticks all of the DSM 5 criteria:

  • Impaired control
    • Using more of a substance or more often than intended
    • Wanting to cut down or stop using but not being able to
  • Social Problems
    • Neglecting responsibilities and relationships
    • Giving up activities one used to care about because of substance use
    • Inability to complete tasks at home, school or work
  • Risky use
    • Using in risky settings
    • Continued use despite known problems
  • Physical dependance
    • Needing more of the substance to get the same effect (tolerance)
    • Having withdrawal symptoms when a substance isn’t used


Become aware of your sugar habits, start learning how to read food labels to discover hidden sugars and as you cut down on sugar, you’ll find that you desire it less.

If you have anything you want to ask, or if there’s a topic you’d like me to write about just let me know. 

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