Can skipping breakfast really cloud your mind? According to new research published by the American Psychological Association, most healthy adults don’t need to worry.
A meta-analysis of 71 studies involving more than 3,400 participants found that short-term fasting, typically around 12 hours, does not significantly affect memory, decision-making or reaction time. In other words, your mental sharpness appears to stay steady even if you’ve missed a meal.
“Across a broad range of diverse tasks, cognitive performance remained remarkably stable,” said lead author David Moreau, PhD, of the University of Auckland. “Many people believe that missing a meal leads to immediate declines in mental acuity, but our synthesis of the evidence suggests otherwise.”
The findings, published in Psychological Bulletin, challenge the long-held belief that hunger automatically dulls focus. While fasting triggers metabolic changes, shifting the body from using glucose to burning fat for fuel, the researchers found that these short-term adjustments don’t appear to disrupt brain function in healthy adults.
Interestingly, context mattered. Performance dips were mostly seen when tasks involved food-related cues such as looking at pictures of food, suggesting hunger may distract attention toward food rather than slow overall thinking.
The study also revealed one important difference by age.
“Age was a powerful and salient moderator,” Moreau said. “Children showed noticeable declines in performance while fasting, echoing earlier studies that highlighted the steady cognitive advantages of eating breakfast in younger age groups.”
For adults, the takeaway is simple. Occasional fasting or skipping breakfast is unlikely to harm focus or decision-making in the short term. But for kids, whose brains rely more heavily on steady energy, breakfast still plays an important role.
“The primary takeaway is a message of reassurance,” Moreau said. “Cognitive performance remains stable during short-term fasting, suggesting that most healthy adults need not worry about temporary fasting affecting their mental sharpness or ability to perform daily tasks.”
This research was supported by the Royal Society of New Zealand Marsden Fund and a University of Auckland Early Career Research Excellence Award to Moreau.