Scientists reveal how seven days of fasting transforms the human body

Scientists have discovered that the human body undergoes a dramatic internal transformation during extended fasting, with major changes appearing only after about three days without food. In a seven-day water-only fasting study, researchers tracked thousands of proteins in the blood and found widespread shifts affecting organs throughout the body — including the brain. While the body quickly switches from burning glucose to fat, the most intriguing biological changes linked to potential health benefits didn’t emerge until later in the fast.