Big Review Finds Short-Term Fasting Leaves Brainpower Largely Unchanged

An analysis of 63 studies (3,484 participants) found no meaningful difference in cognitive performance between short-term fasters and those who eat regularly, with median fasting around 12 hours. Some modest declines appear when fasting exceeds 12 hours and in children/teens, especially on food-related tasks; neutral tasks are largely unaffected and performance may dip later in the day during fasting. The authors frame fasting as a personal tool, not a universal prescription, recommending medical guidance for individuals considering fasting.