- Better Brain Project
- Apr 22
- 2 min read
Updated: Jun 8
New research from the University of Sydney links fatty, sugary diets to impaired
brain function. The findings build on a growing body of evidence showing the
negative impact of high-fat, high-sugar (HFHS) diets on cognitive ability, adding to their well-known physical effects.
Published in the International Journal of Obesity, the research is the first to test in
humans the relationship between HFHS diets, and spatial navigation. Spatial navigation is the ability to learn and remember a path from one location to another, a process that can approximate the health of the brain’s hippocampus.
Dr Dominic Tran from the Faculty of Science’s School of Psychology led the
research, which found HFHS diets have a detrimental effect on some aspects of
cognitive function. It is likely those effects centre on the hippocampus, the brain
structure important for spatial navigation and memory formation, rather than
acting across the entire brain.
The research team recruited 55 university students aged between 18 and 38. Each participant completed questionnaires capturing their intake of sugary and fatty foods. Their working memory and their body mass index (BMI) was recorded.
The experiment required participants to navigate a virtual reality maze and
locate a treasure chest six times. A seventh trial removed the treasure chest from the virtual maze but asked participants to find and mark its former location based purely on memory. Those with lower levels of fat and sugar in their diets were able to pinpoint the location with a higher degree of accuracy than those who consumed these foods multiple times a week.
Dr Tran said the results highlight the importance of making good dietary choices to maintain healthy brain function.
Dr Tran said the sample group used in this research was not representative of the wider population, but the findings still apply more broadly.
“It’s likely our participants were a little healthier than the general population and
we think, if our sample better represented the public, the impact of diet on spatial
navigation would likely be even more pronounced.”
Source
Reference: Tran DMD, Double KS, Johnston IN, Westbrook RF, Harris IM.
Consumption of a diet high in fat and sugar is associated with worse spatial
navigation ability in a virtual environment. Int J Obes. 2025. doi: 10.1038/s41366-
025-01776-8
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