Cognitive Performance Remains Stable During Short-Term Fasting for Adults

MONDAY, Nov. 10, 2025 (HealthDay News) — Cognitive performance remains stable during short-term fasting, according to a review published online Nov. 3 in Psychological Bulletin.

Christoph Bamberg, from Paris Lodron University Salzburg in Austria, and David Moreau, Ph.D., from the School of Psychology and Centre for Brain Research at the University of Auckland in New Zealand, conducted a systematic literature review to assess the acute effects of fasting on cognitive performance. The analysis synthesized evidence from 71 experimental studies comparing cognitive performance between fasted and satiated healthy adults using standardized psychological tasks.

The researchers found that across 222 effect sizes (3,484 participants with a median fasting duration of 12 hours), a hierarchical random-effects model showed no meaningful difference between fasted and satiated participants (g = 0.02; 95 percent credible interval, −0.05 to 0.10). There was low between-study heterogeneity observed (τ = 0.17; 95 percent credible interval, 0.08 to 0.25). There were modest reductions in cognitive performance seen for longer fasting intervals and for younger versus older participants during fasts. Across cognitive domains (e.g., attention and inhibitory control), differences did not reliably explain the heterogeneity in effect sizes.

“The primary takeaway is a message of reassurance: 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,” Moreau said in a statement.

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