Healthy Food, Healthy Brain

In a recent article in The Conversation, Amy Reichelt, an Adjunct Senior Lecturer, Nutritional neuroscientist, University of Adelaide, talks about a decades old myth that eating sugary foods and drinks causes children to be hyperactive.

Balanced nutrition is critical during childhood. As a neuroscientist who has studied the negative effects of high sugar “junk food” diets on brain function, I can confidently say excessive sugar consumption does not have benefits to the young mind. In fact, neuroimaging studies show the brains of children who eat more processed snack foods are smaller in volume, particularly in the frontal cortices, than those of children who eat a more healthful diet.

– Amy Reichelt on The Conversation

According to Amy Reichelt, the myth f sugar-induced hyperactivity can be traced to the Feingold Diet studies conducted in 1970s and 1980s as a treatment for what Attention Deficit Hyperactivity Disorder (ADHD). She says that Feingold Diet study had some flaws, as it didn’t included adequate control group. “Subsequent studies suggested less than 2% responded to restrictions rather than Feingold’s claimed 75%. But the idea still took hold in the public consciousness and was perpetuated by anecdotal experiences.”

  • Rigorous research conducted by experts has consistently failed to find a connection between sugar and hyperactivity. Numerous placebo-controlled studies have demonstrated sugar does not significantly impact children’s behaviour or attention span.
  • One landmark meta-analysis study, published almost 20 years ago, compared the effects of sugar versus a placebo on children’s behaviour across multiple studies. The results were clear: in the vast majority of studies, sugar consumption did not lead to increased hyperactivity or disruptive behaviour.

While the connection between sugar and hyperactivity remains uncertain, there’s a clear association between dopamine, a neurotransmitter, and increased activity. Dopamine is released in response to rewards, like sweets, stimulating movement similarly to psychostimulant drugs such as amphetamine. Children’s excited behavior around sugary foods may stem from the anticipation of a dopamine release, albeit smaller than that caused by drugs. ADHD is closely linked to dopamine function, with treatments like methylphenidate and lisdexamfetamine acting as psychostimulants to adjust dopamine levels, which improve focus and behavior control in ADHD brain.

Healthy Foods, Healthy Brains

Sugar may not directly cause hyperactivity in children, but it can impact their overall mental and physical well-being. Instead of vilifying sugar, it’s important to promote moderation and balanced nutrition, instilling healthy eating habits and fostering a positive relationship with food.

The World Health Organization recommends limiting free sugar intake to less than 10% of energy intake, with further health benefits seen with a reduction to 5%. Using sugary foods as rewards can lead to their overvaluation by children, so it’s advisable to employ non-sugar rewards like stickers or activities for positive behavior reinforcement.

While sugar may offer a temporary energy boost, it doesn’t transform children into hyperactive individuals, says Reichelt.