How the body responds during long periods of fasting : Medical Press

A new study reveals that the body's organs undergo major systematic changes during long periods of fasting from food.

Millions of people around the world tend to follow the fasting system for many purposes, such as obtaining health benefits and losing weight.

During fasting, the body changes the source and type of energy, switching from consumed calories to using its own fat stores. However, little is known about how the body responds to long periods without food.

Researchers at the Queen Mary Precision Healthcare Research Institute (PHURI) and the Norwegian College of Sports Sciences identified the potential health benefits of fasting and their underlying molecular basis by measuring thousands of proteins circulating in the blood, which could lead to important therapeutic interventions.

The research team followed 12 healthy volunteers who participated in “water fasting” only for seven days, and recorded changes in the levels of approximately 3,000 proteins in the blood before, during, and after fasting, to predict the potential health consequences of fasting for long periods by integrating genetic information from large-scale studies.

The researchers noted that the body switches energy sources (from glucose to fats stored in the body) during the first two or three days of fasting.

It was found that the volunteers lost about 5.7 kg of fat mass and fat-free mass. The weight remained stable after 3 days of eating after fasting, but the fat mass remained the same.

The researchers also observed "for the first time" that the body experiences clear changes in protein levels after 3 days of fasting, indicating a whole-body response to complete calorie restriction.

Overall, 1 in 3 proteins measured changed significantly during fasting in all major organs. There were distinctive signs of fasting, such as changes in the proteins that form the supporting structure of nerve cells in the brain.

Claudia Langenberg, Director of the Queen Mary Research Institute (PHURI), said: “For the first time, we are able to see what happens at a molecular level throughout the body when we fast. Our results provide evidence of the health benefits of fasting that go beyond weight loss, but these benefits "It was not visible until after 3 days of total calorie restriction."

The study was published in the journal Nature Metabolism.