Diet & Nutrition 4 MIN READ 82 VIEWS May 26, 2022

Effects of Sugar on the Brain You Might Not Know About

Written By HealthKart
Medically Reviewed By Dr. Aarti Nehra

Effects of Sugar on the Brain
Negative Effects of Sugar on the Brain
Why Do We Crave Sugar if It is Bad for Us
How to Manage Sugar Consumption

We have often heard of the harmful effects of consuming sugar excessively. It impacts every part of the body. When the glucose level in the blood is elevated, it has an adverse effect on your overall body function. Did you know that there are several harmful effects of sugar on the brain? Sugar impacts your cognitive abilities and may even impair your memory. Here is everything you need to know about the effects of high blood sugar on the brain and how you can control your sugar intake. 

Negative Effects of Sugar on the Brain 

The human brain is one of the most energy-demanding organs in the body. It has so many neurons that require a consistent energy supply that it uses 50% of all the energy produced by assimilating sugar. In fact, when you have low glucose levels in the bloodstream, it can cause a breakdown in communication between the neurons. This leads to poor cognitive function and attention. 

While the brain depends on sugar for proper function, excessive sugar is also a bad thing. A study conducted by the University of Montreal in 2009 showed that excessive glucose consumption is directly linked to cognitive deficiency and memory loss. This impact of sugar is due to overstimulation of the brain, causing mood swings and other issues. Here are some harmful effects of high blood sugar on brain: 

1. Memory Difficulties 

If you or someone you know deals with diabetes, then you should know that one of the most common diabetes effects on the brain is the disruption in memory. When the sugar level in the blood is higher than the normal amount, it leads to inflammation in the brain. This is known to cause issues with memory. A study published in 2016 in ‘Behavioural Brain Research,’ showed that rats that were given a high sugar diet showed inflammatory markers in the brain. This was absent in rats that were given a standard diet. This effect, luckily, is not permanent. The inflammation can be reduced by using Omega-3 supplements and reducing daily sugar intake. 

2. It Affects Your Mood

Excessive sugar consumption is related to mood swings. Brain imaging studies have revealed that high blood glucose levels reduce our ability to process emotion. One of the effects of sugar on the brain is feelings of anxiety and sadness. 

A study conducted on over 20,000 individuals linked depression with sugar consumption. It showed that higher sugar consumption increased the incidence of depression. Studies have also shown that people with higher levels of sugar consumption are more likely to be diagnosed with mental disorders than those who consume less sugar. 

3. It Impairs Cognitive Function 

Elevated blood sugar for long periods is known to cause learning issues, impaired motor speed, memory loss, and other cognitive issues. It has also been observed that test scores are lower in individuals who tend to consume more sugar. 

These effects of sugar on the brain are linked to the damage caused to the blood vessels. Long term uncontrolled high blood sugar level causes vascular complications that can damage the blood vessels in our brain. It might also lead to shrinkage in the size of the brain, reducing your overall cognitive abilities. 

There is also some evidence that suggests that high sugar intake reduces the production of Brain-Derived Neuropathic Factor or BDNF. This is a type of chemical in the brain that is essential for learning and the formation of new memories. In individuals with Alzheimer’s, low BDNF levels are often observed. 

Why Do We Crave Sugar if It is Bad for Us? 

Even though we understand the harmful effects of sugar on our health, we crave sugar. The brain is wired to crave sugar-rich foods because they are an instant energy source. There are other causes for this: 

  • The dopamine ‘hit’: Since sugary foods are the best energy sources, humans have evolved to find these foods more pleasurable. Our brain has an innate need for sugar in order to maximise our chances of survival. Our brain’s reward system gets activated whenever we eat sugar, thus, releasing dopamine. This is a feel-good neurotransmitter that makes us repeatedly crave sweet foods.  
  • Sugar rewires the brain: The brain learns and modifies itself constantly through neuroplasticity. Since sugary foods activate the reward system, we begin to adapt to higher levels of stimulation. It also causes tolerance which means that we need more each time to experience that reward. 

Therefore, when it is uncontrolled, sugar can be addictive. So, it is imperative for us to watch our sugar consumption. 

How to Manage Sugar Consumption? 

While sugar is necessary for the brain to function, its consumption must be moderate. According to the World Health Organisation, it is best to limit sugar intake to about 5% of the daily calorie intake. This is roughly six teaspoons for a healthy adult. Here are some tips to reduce consumption and the harmful effects of sugar on the brain

  1. Consider sources like fruits which are free from refined sugar. 
  2. Instead of drastically cutting down on sugar, reduce it slowly. The brain can learn and reset itself to function on moderate sugar consumption. 
  3. Physical exercise makes it easier for the brain to adapt to the reduced sugar intake. 
  4. Foods rich in Omega-3 are highly beneficial in boosting the brain chemicals required for various cognitive functions. 
  5. Eating fibre-rich foods gives you a source of sugar but also keeps you feeling fuller for longer, reducing cravings considerably. 


While it is not easy to cut down on your favourite desserts or sweets, the effects of sugar on the brain are a reason enough to keep you motivated. You will begin to see the difference as you commit to consuming a healthy, nutritious, and balanced diet.

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