Overview
- The synthesis pooled 71 studies with 3,484 participants, most involving short fasting windows near 12 hours.
- Across measures such as memory, decision-making, response speed and accuracy, healthy adults showed no consistent impairment during short-term fasting.
- Modest declines appeared when fasting extended beyond about 12 hours, and effects were more pronounced in children than in adults.
- Deficits were mainly observed on tasks featuring food-related cues, whereas performance on neutral-content tasks was largely unchanged.
- Authors say the findings support the feasibility of intermittent fasting for most adults but urge tailored caution for children and clinical populations, noting performance tended to dip later in the day in some tests.