Fasting diets may make you smarter Gergely Kishonthy / Alamy Stock Photo

Could regular fasting make you smarter? People following regimes like the popular 5:2 diet usually do so for weight loss, but some who try it say it makes them mentally sharper too.

If this is true, experiments in mice may have explained why. In these animals, fasting has been found to cause changes in the brain that likely give neurons more energy, and enable them to grow more connections.

Mark Mattson of the National Institute on Aging in Bethesda, Maryland and his team looked at 40 mice, …