Sugar causes people to perform worse on tests of memory and thinking skills, new research finds.
Participants consuming either table sugar (glucose) or fruit sugars (fructose) were worse at math, had slower reactions and showed poorer attention than a control group who had a sweetener.
The study suggests that what is sometimes called a ‘sugar coma’ — a slow down caused by sugary foods — could be a real effect.
Being very hungry before consuming the sugar made the brain’s performance even worse, the researchers also found.
The study’s authors write:
“…ingestion of glucose and sucrose led to poorer performances on the assessed tasks as opposed to fructose and the placebo; these effects were particularly pronounced under the fasting condition in comparison to the non-fasting condition.”
The study was a double-blinded placebo-controlled experimental design.
People who consumed a sweetener did not see any deficit in their cognitive performance.
This suggests it is not the sensation of sweetness, but rather the effects of sugar itself.
About the author
Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology.
He has been writing about scientific research on PsyBlog since 2004. He is also the author of the book “Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks:
- Accept Yourself: How to feel a profound sense of warmth and self-compassion
- The Anxiety Plan: 42 Strategies For Worry, Phobias, OCD and Panic
- Spark: 17 Steps That Will Boost Your Motivation For Anything
- Activate: How To Find Joy Again By Changing What You Do
The study was published in the journal Physiology & Behavior (Ginieis et al., 2018).