16 Reasons Why Sugar Is Bad For You

Like most people, you probably know that eating too much sugar is bad for you. But do you know exactly why?

Everyone knows that sugar is bad for you, but most people don’t know why. In this blog post, I will discuss the negative effects that sugar has on your body and health. To understand exactly why sugar is bad for you, it helps to start at the beginning—how you get sugar in the first place.

Sugar is called “sugar” because it comes from plants with sugary juices, like sugar cane and sugar beets. The most common type of sugar in food is called sucrose, which is the main ingredient in table sugar. Other types of sugars, such as fructose, glucose and lactose, also occur naturally in some foods.

Your body needs some sugar to function properly. The carbs and sugars you eat give your body energy and fuel it can use right away. But once you’ve eaten more than your body needs right away, your body can store the extra carbs and sugars as glycogen. Any of the extra that your body doesn’t use right away gets turned into fat and stored in your body for later use.

So, what’s so bad about eating sugar?

Why is sugar bad for you?

It turns out that our bodies just don’t deal with carbohydrates and sugars very well, especially when we eat them in large quantities. Below I discuss some of the main reasons why eating too much sugar is bad for you.

Sugar causes: 

  1. Chronic inflammation
  2. Oxidative stress
  3. Moodiness and tiredness
  4. Bad bacteria grow in the gut
  5.  Parasites to grow
  6. Weight gain
  7. Cold & flu viruses to thrive
  8.  Sleeping challenges
  9. Difficulty to concentrate
  10. Problem to exercise
  11. Worsens depression
  12. Higher risk of type 2 diabetes
  13. Increased risk of heart disease and stroke
  14. Headaches and migraines
  15. Increased risk of cancer
  16. Problems with fertility
"Make one healthy choice. then make another." - Unknown
"Make one healthy choice. then make another." - Unknown

Sugar causes chronic inflammation

Sugar, more specifically fructose, is bad for you because it causes chronic inflammation throughout the body.

This inflammation is caused by the overproduction of cytokines, small protein molecules that form part of the immune system (Corte & Buyken, 2018).

Cytokines are responsible for protecting us from foreign invaders such as viruses and bacteria, but also cause chronic inflammation in our bodies.

Chronic inflammation can cause fatigue, joint pain, and sore muscles. In fact, it wears down our bodies just as much as lack of sleep or stress.

That’s why you might want to cut down on sugar – especially fructose – which can turn into fat in the liver and make existing inflammation worse.

Sugar causes oxidative stress

Not only does sugar cause chronic, internal inflammation. It also bad for your healthy because it causes oxidative stress, which is caused by free radicals in the body (Markham Integrative Medicine, 2018).

Free radicals are unstable molecules that cause damage to healthy cells – just like rusting or rotting does to metal or wood.

Oxidative stress reduces cellular reproduction and function over time. The effects of oxidative stress include accelerated aging, brain degeneration, cardiovascular disease, and even cancer.

Sugar is one of the main causes of oxidative stress because it increases free radical production in the body.

Sugar makes you moody & tired

If you often feel moody or tired after eating sugar, it’s not in your head. Sugar is bad for you because it causes a quick rise of serotonin levels – serotonin is the hormone responsible for regulating mood and appetite in the body. 

This rise causes an energy-boosting spike, which can make you feel more awake and alert. However, this is only very short-lived.

Unfortunately, after serotonin levels peak they quickly decrease, which causes you to feel irritable, moody, and lethargic too.

Plus, too much sugar will cause our blood sugar levels to spike. Subsequently, our body releases insulin to help regulate the glucose levels. If our body produces too much insulin in response to a sugar spike, it can cause our blood sugar levels to drop too low, leading to feelings of fatigue, weakness, and hunger.

This is commonly called “sugar crash.”

This is the same kind of cycle experienced by drug addicts – who also experience mood swings and cravings.

That’s why you might want to cut down on your sugar intake if you want to feel better both mentally and physically.

Check out this daily routine to maintain wellness

Check out this daily routine to maintain wellness
"To keep the body in good health is a duty, otherwise we will not be able to keep our mind strong and clear." - Buddha

Sugar makes bad bacteria grow in the gut

The microbiome is a community of trillions of microbes that live inside us and on our skin. The majority of these are bacteria, which help us break down food and fight off infections. But, not all bacteria are helpful.

You probably know that our gut contains “good” bacteria – bacteria that help us digest food and make some vitamins – but there are also bad bacteria in our gut, such as those responsible for chronic inflammation (mentioned above), depression, and weight gain.

Since sugar feeds all bacteria, good and bad, you might want to cut down on your intake of sugary foods if you want to avoid weight gain, chronic inflammation, and depression.

Sugar makes it easy for parasites to grow in the gut

Parasites are yet another type of microorganism that can make us sick. Not only do they live in our food, but they also live inside us – without us knowing it.

And because sugar feeds parasites as well as the good and bad bacteria already mentioned above, you might want to cut down on your intake of refined sugars such as table sugar and high-fructose corn syrup if you want to starve those parasites.

Sugar promotes weight gain

It’s well-known that sugar promotes weight gain. In fact, it contains almost no nutrients, which means it doesn’t fill you up for long – but it can make you put on weight quickly.

Because sugar is metabolized into fat cells in the body, high consumption of refined sugars can lead to obesity over time.

This is bad for your heath because obesity increases your risk of chronic inflammation, diabetes, and cardiovascular disease.

As such, to lose or control your weight and avoid chronic inflammation, tooth decay, and diabetes (and maybe even cancer), you might want to cut down on sugar as much as possible.

Sugar makes cold & flu viruses thrive

Just like bad bacteria, cold and flu viruses need sugar to grow. Many cold and flu viruses use the sugar in our bodies as a source of energy.

The more sugar, the faster these viruses can grow and spread through your system.

So, if you want to avoid getting sick during the cold season, it might be a good idea to cut down on sugary snacks now – especially those that are not natural sources of sugar, such as candy, processed foods, and soft drinks.

Discover why sugar is bad for you.
"Everyone got their poison and mine is sugar." - Derrick Rose

Sugar makes it hard to sleep

When you have a big sugar crash, after eating all those sugary snacks, your body releases adrenalin to compensate.

This can keep you up at night because the adrenalin also makes you more alert – even if your brain is exhausted from a long day at work.

Even when you do fall asleep, you’ll likely sleep less deeply and be more restless.

This is why some people like to eat sugary snacks before bedtime – but if you want a good night’s sleep, it might be a better idea to avoid them and opt for something less energizing instead (such as milk or whole-grain cereal).

You’ll be more relaxed and your body will thank you for it tomorrow morning.

Read also: 27 Healthy habits to naturally improve your sleep

Sugar makes it hard to concentrate

You might want to cut down on sugar if you experience a spike in your energy levels after eating sugary snacks, which can make you feel more awake and alert – but this is followed by a crash that can make you feel tired and groggy again.

These sugar crashes are bad for you because they can also make you feel scatterbrained and unfocused – especially if they happen several times throughout the day.

So, if you want to be more productive at work (and maybe even stay awake), it might be helpful to cut down on sugary snacks now.

Sugar makes it hard to exercise

Adrenalin isn’t the only reason why sugar makes it hard to concentrate and focus. Sugary snacks can also cause you to feel fatigued, exhausted, and even nauseous.

This is because the excess sugar in your blood stimulates insulin production – which sends nutrients into your cells to be stored as energy.

This means you have less energy available for physical activity such as exercise, which can cause you to feel tired, lethargic, and even nauseous.

This might be just what you need now if you aim to lose weight, but it’s probably not what you want right now if you’re trying to stay in shape or perform well during exercise.

Sugar makes depression worse

Sugar is addictive. It might only be mildly so, but the feeling you get after eating sugary snacks can sometimes feel like a high – and the sudden drop in energy levels after your body releases insulin to process the sugar in your blood can feel like a low.

This rollercoaster of highs and lows is bad for you because it means that if you’re already suffering from depression or some other mental illness, you might want to cut down on sugar as much as possible.

Not only does it make you more likely to develop depression (because of the excess energy release followed by an even bigger energy crash), but when you’re in the grip of a depressive episode it can make your symptoms worse – which is why some people find it difficult to motivate themselves to eat anything at all.

You might like sugar because of the way it makes you feel. But, you’ll soon realize how destructive it can be if you continue to eat sugary snacks every day.

There are several reasons why sugar is bad for you
"Eat less sugar. You're sweet enough already." - Unknown

Sugar increases the risk of type 2 diabetes

The more sugary snacks you eat, the more likely you are to become overweight or even obese – which in turn increases your risk of developing type 2 diabetes because being overweight causes insulin resistance.

Insulin is produced in response to elevated sugar levels in your blood… so when there’s too much sugar around, your body produces too much insulin, which means your body can’t use it effectively. This is what causes insulin resistance.

If this sounds familiar, cutting down on sugary snacks might be the only thing standing between you and a healthy weight – so try to cut back as much as possible if you want to decrease your likelihood of developing type 2 diabetes.

Sugar can lead to an increased risk of heart disease and stroke

Weight gain due to an excess sugar in your blood is directly responsible for the plaque that builds up on artery walls, which makes it more likely you’ll suffer from clogged arteries or even an increased risk of heart disease and stroke.

Plus the additional insulin produced as a result of excess sugar causes the wall of your arteries to inflame and thicken.

You might not be able to avoid this if you’re unfortunate enough to have a family history of heart disease, but by cutting down on sugar in all its various forms as much as you can now, you’ll reduce the risk of developing heart disease and stroke in the future.

Sugar can trigger headaches and migraines

People who suffer from frequent headaches or even migraines might want to think about cutting down on sugar because eating sugary snacks can cause migraines and increase the number of headaches you suffer from.

This is mostly due to the hormonal fluctuation I described earlier.

Eating foods high in sugar was actually one of the biggest migraine triggers, which means it’s not only cutting down on your intake of sugary snacks throughout the day.

But, if you find yourself feeling a bit hungry or sluggish, don’t reach for sugary snacks to give you a boost – try reaching for some healthy foods instead.

Sugar can increase the risk of developing cancer

Although it’s sometimes difficult to directly link eating sugar with developing cancer, excess sugar in your blood is bad for you because it can cause insulin resistance, obesity and oxidative stress which are all known to increase the risks of various forms of cancer.

So, in order to reduce your risk of cancer, try cutting down on sugary snacks as much as you can – or even better, cut them out completely from your diet.

Sugar is bad for you because of the numerous health consequences which include...
"It's not a short term diet. It's a long term lifestyle change." - Unknown

Sugar might make it more difficult for you to fall pregnant

Finally, eating a lot of sugar is bad for you because it can have a significant impact on fertility in both men and women.

In particular, there’s some evidence to suggest that a diet high in sugar can have a negative impact on sperm quality in men and egg quality in women, which isn’t good news for anyone who’s trying to fall pregnant naturally or through assisted contraception methods like IVF treatment (Open Access Government, 2021).

Final words on why sugar is bad for you

Undeniably, sugar can sometimes be very harmful to your health. Sugar causes chronic inflammation throughout the body.

This causes fatigue, joint pain, and sore muscles – which means that sugar essentially can make you feel ‘old before your time.’ 

If you cut down on sugary snacks now, you might find that you become healthier and happier – not just during cold season but all year round.

Read more on healthy living now, or check out the related articles below.

Read also: 8 Simple ways to be healthier

Related topics

How can I decrease my sugar intake?

If you’re like most people, you enjoy a sweet treat every once in a while.

But if you’re looking to cut down on your sugar intake, it can be tough to know where to start. 

In this blog post, we’ll share some tips for reducing your sugar intake, so you can feel your best. Read more

How can I stay committed to healthy eating?

There is no denying that healthy eating is important, but it can be tough to stay committed to a healthy diet.

Here are a few tips to help you stay on track:

  • Make sure you have plenty of healthy options available. If all you have in your fridge are unhealthy snacks, you’re going to be more likely to give in and indulge.
  • Try not to deprive yourself. If you completely avoid all your favorite unhealthy foods, you’re going to be much more likely to cheat. Moderation is key.
  • Be prepared for setbacks. Everyone makes mistakes sometimes, so don’t beat yourself up if you slip up now and then. Just get back on track as soon as possible. Read more


Della Corte, K. W., Perrar, I., Penczynski, K. J., Schwingshackl, L., Herder, C., & Buyken, A. E. (2018). Effect of Dietary Sugar Intake on Biomarkers of Subclinical Inflammation: A Systematic Review and Meta-Analysis of Intervention Studies. Nutrients10(5), 606.

Open Access Government (2021) What effect can sugar have on fertility?

Markham Integrative Medicine (2018) How Sugar Fuels Oxidative Stress. 

Song M. (2020). Sugar intake and cancer risk: when epidemiologic uncertainty meets biological plausibility. The American journal of clinical nutrition112(5), 1155–1156.

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