If you’ve ever wandered around a parking lot wondering where you left your car, you might want to check your snack habits. A new study suggests that eating a diet high in fat and sugar could make you worse at spatial memory—the kind your brain uses to remember where things are in physical space.

Published in Nature’s International Journal of Obesity, the study used virtual reality to mimic real-world navigation and examined how diet might be affecting our internal sense of direction. The result? People who regularly consumed fast food, soda, and sugary snacks were less accurate and slower to improve at spatial tasks—even if they were otherwise healthy and cognitively sharp.

“Eating healthy is important for your physical health and brain health,” said lead researcher Dominic Tran

The Virtual Treasure Hunt

The researchers recruited 120 university students, but due to motion sickness and technical issues, only 55 completed the full experiment.

In the task, participants navigated a virtual maze to find a hidden treasure chest, using landmarks—like trees and towers—to guide them. It’s the digital equivalent of remembering where you parked at the mall by spotting nearby signs or buildings.

Over six trials, most participants got better and faster at finding the chest. But those who reported eating more high-fat, high-sugar foods improved less—their learning curve was flatter. And in the final test, when the maze’s walls were removed and only the landmarks remained, those with unhealthier diets performed significantly worse.

Even after accounting for body mass and working memory (a measure of general cognitive ability), the effect still held—suggesting a specific link between diet and spatial memory.

The Brain Behind the Behavior

The area of interest here is the hippocampus, a brain region critical for memory and navigation. The study supports the idea that diets heavy in junk food may selectively impair hippocampal function, without affecting broader cognitive abilities like working memory.

Also, the study was correlational, not causal, the study provides strong evidence that the most likely explanation is that poor diet does, in fact, impair hippocampal function.

This study adds to the growing body of research showing that what you eat affects more than just your waistline—it may also affect your ability to navigate and orientate your surroundings.

The study fuels more evidence that ultra-processed foods and foods high in fat is harmful for the brain, while other evidence have shown that a whole, food plant-based diet is beneficial.

DMD Tran et al. Consumption of a diet high in fat and sugar is associated with worse spatial navigation ability in a virtual environment. Nature’s International Journal of Obesity. https://doi.org/10.1038/s41366-025-01776-8