Large-scale analysis reveals negative effects of sugary foods on memory.
It is believed that humans developed a liking for sugar in the days of hunter-gatherer lifestyles as an efficient way to obtain high-calorie foods. However, in recent years, sugary drinks and sweets have become readily available anytime, anywhere. A new analysis of more than 20 studies has revealed the negative effects of sugary diets on the brain.
Cognitive and behavioral effects of high-fat, high-sugar diet reversal: a systematic review and meta-analysis of animal studies
Healthy eating improves memory, but sugary diets may cause lasting damage
https://www.uts.edu.au/news/2026/05/sugary-diets-may-cause-lasting-memory-damage
Large Review Shows What Sugary Diets May Be Doing to Your Memory : ScienceAlert
https://www.sciencealert.com/large-review-shows-what-sugary-diets-may-be-doing-to-your-memory
Previous studies have shown that high-fat, high-sugar diets negatively impact not only physical health but also cognitive functions such as learning and memory. However, it is not well understood how long these negative effects persist after improving unhealthy eating habits.
Therefore, a research team led by Simone Lane, a biopsychologist at the University of Technology Sydney in Australia, conducted a systematic review and meta-analysis of 27 studies using rodents such as rats and mice. They investigated the effects on cognitive function when transitioning from a high-fat, high-sugar diet to a healthy diet. The research team focused on diet and memory, while also tracking other indicators that may indicate an impact on cognitive function, such as general activity levels, appetite, anxiety, and behaviors similar to depressive symptoms.
Mike Kendig, a co-author of the paper and a biopsychologist at the University of Technology Sydney, like Lane, points out that animal models are important for understanding the effects of diet on the brain. 'In humans, changes in diet occur simultaneously with changes in exercise, mood, and daily life, so it is very difficult to isolate the effects of diet on brain function,' he says.
The analysis revealed that rodents fed an unhealthy diet for more than two weeks consistently performed better on memory tests when switched to a healthier diet for at least 24 hours compared to rodents that continued to be fed the unhealthy diet. No consistent improvement was observed in other cognitive function indicators with the dietary change, suggesting that this effect is specific to memory.
Furthermore, the impact on memory varied depending on the original dietary habits. A significant effect was observed in rodents that had been continuously fed a high-fat diet, but little improvement was seen in rodents that had been continuously fed a simple high-carbohydrate diet or a diet that was high in both fat and carbohydrates.
Lane stated, 'We saw a clearer improvement in memory after replacing high-fat diets with healthy diets. However, with diets high in added sugars, especially those high in both fat and sugar, there were hardly any signs of recovery. This suggests that sugar may be a significant factor inhibiting memory recovery.'
The series of effects observed in this analysis are thought to reflect the function of the hippocampus , a brain region essential for learning and memory, and also involved in appetite regulation. Previous studies have shown that high-fat, high-sugar diets impair the hippocampus's appetite regulation function and negatively affect its volume .
In their paper, the research team states, 'These findings suggest that improving dietary habits enhances spatial memory, which is primarily dependent on the hippocampus, and support evidence that the hippocampus is particularly sensitive to changes in diet and other environmental factors.'
Kendig stated, 'It's commonly believed that the effects of an unhealthy diet can be easily reversed. However, these findings suggest that the situation may be more complex, at least in terms of memory, especially with diets high in added sugars. Improving the quality of one's diet remains important. But to protect brain health, it's also crucial to avoid prolonged exposure to an unhealthy diet and not assume that the effects can be completely reversed later.'
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in Free Member, Science, Food, Posted by log1h_ik