How Sugar Affects the Brain

To date, it's been shown that sugar can be addictive and even trigger inflammation. Here, we'll explain how sugar affects the brain.
How Sugar Affects the Brain
Marta Guzmán

Written and verified by Nutritionist Marta Guzmán.

Last update: 25 May, 2022

Sugar can cause numerous health problems. In fact, sugar affects the brain as well. The most concerning thing is that it’s most often present in the foods that we consume frequently. Also, it can be as addictive as many drugs.

Reducing the amount of sugar in the diet is essential to improve your health and prevent disease. In this article, you’ll find out how sugar affects the brain.

Sugar affects the brain

What is sugar?

Different types of sugar.

The first thing that comes to mind when we think of the word sugar is the white sugar we have at home. This is sucrose, and it’s the most common form we can find.

However, there are many more types of sugars depending on their chemical structure. For example, sugars like fructose, galactose, glucose, maltose, or lactose naturally appear in foods. Also, they can be added as sweeteners or preservatives.

Manufacturers can introduce them into food under a wide range of names. Therefore, it’s important to read nutrition labels and know the symptoms of sugar. 80% of the processed products found in the supermarket contain hidden sugars that we consume without realizing it. In fact, these are the ones that we really should avoid.

The WHO recommends reducing the consumption of free sugar (the one added to food, not the one naturally found in them), below 10% of the total caloric intake for the day.

Also, it even encourages dropping the number to 5%, since it would give you additional health benefits. This is stated by research published in the journal Diabetes Research and Clinical Practice. Doing this can help prevent diseases like diabetes, as well as help manage it.

You might be interested: What Are The Differences Between Glucose and Fructose?

How does sugar work in the brain?

The brain, according to a study published in the journal Physiology & Behavior, consumes 5.6 milligrams of glucose per 100 grams of brain tissue per minute. In adult brains, the greatest energy demand comes from neurons.

Even though the brain represents less than 2% of body weight, it spends up to 20% of the total glucose energy manufactured by the body. In other words, the brain is the body’s main glucose consumer.

When you eat foods that contain sugar, when you put them in your mouth and they come into contact with your taste buds, they send signals activating the sweet receptors in the brain stem. Then, from there, they send signals to different areas of the brain, where they activate the brain’s reward system.

In the same way, there are sugar receptors in the digestive system, which will send signals to the brain indicating whether there’s a feeling of safety or not. The effects of sugar on the brain explain why we may have difficulty controlling its consumption.

Produces addiction

Sugar can be addictive, but how does this happen? The main asset of the reward system in the brain is dopamine. Regarding this, it has been shown that if we eat foods rich in sugars, the dopamine response of our brain doesn’t level off.

Therefore, the more sugar we eat, the more reward signals our brain will continue to send. In fact, this is also the case with some drugs like cocaine or heroin.

Because of this, every time you eat any type of sugary food, it activates a gratifying sensation in the brain, producing addictive effects on our brain. There are studies, like the one published in 2018 in the British Journal of Sports Medicine, that affirm that it’s possible to form a sugar addiction.

Increases the risk of certain diseases

We know that excessive sugar consumption is reflected in cardiovascular diseases, diabetes, fatty liver, cancer, and others. However, new findings show that sugar affects the brain negatively, producing inflammation or emotional reactions. 

For example:

  • Infant hyperactivity
  • Fatigue
  • Insomnia
  • Anxiety
  • Dementia
  • Depression

A study published in Scientific Reports, which included 264,000 adults over 50 years of age, with 10 years of follow-up, showed that people who drank more than 4 cans of sugary drinks daily had a greater risk of suffering from depression. In fact, it showed figures of almost 30%, compared to those who didn’t.

Causes memory and learning problems

An elderly woman with memory problems.

Another problem in people who consume sugar in excess, according to scientific studies, is having a poorer memory. In fact, this is because, when there are high levels of glucose in the blood, the brain will try to metabolize it. Then, this can cause damage to the hippocampus.

The hippocampus is the area of the central nervous system that forms, organizes, and stores ideas and memories. In this way, the more sugar the brain gets, the more it becomes saturated. Over time, this could lead to neurological degradation, causing deficiencies in memory and reasoning skills.

Sugar consumption affects the brain negatively

As science shows, there’s a strong relationship between sugar intake and later risk of mental illness. This is because this substance can cause a neurotoxic effect on the brain.

Therefore, eliminate or minimize table sugar, ultra-processed products, breakfast cereals, sauces, and sugary drinks.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Sainsbury E., Kizirian NV., Partridge SR., Gill T., Colgiuri S., Gibson AA., Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: a systematic review and meta analysis. Diabetes Res Clin Pract, 2018. 139: 239-252.
  • Murray S., Tulloch A., Avena NM., Recent studies of the effects of sugars on brain systems involved in energy balance and reward: relevance to low calorie sweeteners. Physiology & Behavior, 2016.
  • DiNicolantonio JJ., O’Keefe JH., Wilson WL., Sugar addiction: is it real? a narrative review. Br J Sports Med, 2018. 52 (14): 910-913.
  • Knuppel A., Shipley MJ., Llewellyn CH., Brunner EJ., Sugar intake from sweet food and beverages, common mental disorder and depression: prospective findings from the whitehall II Study. Sci Rep, 2017.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.