After 70 Years of Studies.. Fasting Does Not Impair Concentration in Healthy Adults

A comprehensive review of the results from 71 scientific studies involving approximately 3,500 participants showed that intermittent fasting does not significantly affect concentration or cognitive performance in healthy adults. The study, which spanned nearly 70 years (1958–2025), analyzed over 200 tests measuring attention, memory, and executive functions such as planning and decision-making, concluding that performance levels are similar between fasters and non-fasters.

How does the body adapt during fasting?

Researchers indicate that after about 12 hours of food abstinence, the body begins to use fat as an energy source, producing ketone bodies that efficiently fuel the brain. This natural metabolic shift enables the mind to maintain cognitive performance during periods of food scarcity, a evolutionary mechanism that has supported humans throughout history.
Additionally, fasting is associated with improved insulin sensitivity and the activation of "autophagy," which contributes to cell renewal and supports healthy aging, making intermittent fasting beneficial for both the body and the brain.

Most Affected Groups by Fasting

Despite the encouraging results for adults, data showed that children and adolescents are more sensitive to energy fluctuations and may experience performance impacts when skipping meals. Furthermore, there may be a slight decline in performance among fasters when tests are conducted later in the day or during food-related tasks, while neutral tasks remain stable in performance.

A Message of Reassurance Before Ramadan

The study indicates that abstaining from food for long hours does not mean losing mental sharpness in healthy adults, reassuring fasters before the month of Ramadan. However, consulting specialists remains essential for those with specific health conditions or dietary needs.

After seven decades of research, it seems that the common belief that "hunger weakens the mind" needs to be revisited. The adult brain is more capable of adapting during fasting than previously thought, maintaining focus and mental performance.