Can excess sugar affect the developing brain?

Adapted from Lina Begdache, a clinical nutritionist who writes for The Conversation.

Sugary foods are everywhere – particularly during childhood when sweet treats seem to be a part of life.  Parents often stress about their children’s sugar intake, but exactly how much is too much, and what can be done about it?

Our brains are hungry.  They need a continuous source of energy and nutrients to fuel growth, learning and development because they cannot store energy.  Glucose—a simple sugar that forms the basis of most carbohydrate-rich food (bread, rice, potatoes, pasta)—is the primary source of energy for the brain.  However, that doesn’t mean extra consumption of sugar is good for the developing brain. In fact, too much sugar can actually be detrimental to the normal growth of the brain. 

Preliminary results from research indicate that consumption of sugary food is associated with mental distress—such as anxiety and depression—and disrupted sleep. 

Sources of sugar in kids’ diet

Processed foods, such as donuts, cooldrinks and sweetened cereals, often contain added sugars. Unfortunately, these foods tend to be easily accessible to children and teenagers—whether it be after sports games or at birthday parties. 

Chemically processed foods are those that have been altered by adding components not naturally found in them. These foods often contain added sugars, preservatives, salts and trans fats—all aimed at increasing taste, texture or shelf life. 

As a result, processed foods have a lower nutritional value than whole foods, such as fruits, vegetables and whole grains.

Excess sugar puts the brain in overdrive

Because glucose is the primary source of energy to the brain, too much sugar can put it into an overdrive mode. When the brain is overstimulated, it can lead to hyperactivity and mood swings. However, these behavioural changes are only the short-term consequences. Some evidence suggests that this brain hyperactivity in adolescents is linked to cognitive deficits in adulthood. 

Sugar also has an addictive effect because it stimulates neurons in the brain’s reward system, known as the limbic system. When activated, the limbic system generates high emotions such as pleasure, which leads to a desire for more sugar.

In addition, within the limbic system there is a tiny structure called the amygdala, which processes emotional information. Overactivation of the amygdala is associated with exaggerated emotions such as fear and anxiety. 

Research suggests that there is a strong relationship between high sugar consumption, altered behaviour and poor emotional regulation. Although sugar intake may boost mood momentarily, chronic sugar consumption has been linked with increased risk of mental health problems. 

Studies in lab animals also suggest that high consumption of sugar hinders learning and memory. Interestingly, daily intake of sugar-sweetened beverages during teenage years is associated with worsening of performance on a learning and memory task during adulthood. The researchers of that study suggest that this impairment could be due to alterations in gut bacteria. 

Considering the mounting body of evidence, the seemingly irresistible sweetness of sugar can translate into a bitter outcome for the developing brain.



Contact Details



+27 (0) 21 873 4951
+27 (0) 82 559 9966
+27 (0) 82 414 4814
+27 (0) 86 691 0051

Email  Find an ILT Practitioner near you