Intermittent fasting (IF), long practiced as a religious ritual, has gained significant popularity as a tool for weight loss and overall health improvement. A 2024 survey found that 13% of Americans had followed an IF regimen in the past year. Mark Mattson, PhD, a neuroscientist at Johns Hopkins University, explains that IF is not a diet but rather a structured pattern of eating, focusing on when and how often food is consumed rather than specific food choices. IF works by alternating periods of energy deficit, such as fasting or exercise, with periods of energy intake and rest, potentially optimizing both general and brain health.