Week-long fasting triggers significant physiological changes, scientists find

For centuries, fasting has occupied the borderlands between spiritual discipline and dietary folklore, but science is now bringing it into sharper focus. New research documents, with biological precision, the cascade of metabolic and cellular transformations that unfold across seven days without food — changes that go well beyond simple calorie reduction. By mapping the timeline and magnitude of these shifts through measurable markers, researchers are laying the groundwork for a more rigorous, personalized understanding of what fasting actually does to the human body, and for whom it might mat