What happens in the body during a seven-day fast: results of a new study
- 12 volunteers underwent a seven-day fast without food
- Changes in the levels of ~3000 proteins began to manifest after 3 days
- The average weight loss was 5.7 kg (fat and muscle mass)
- The study may serve as a basis for fasting-mimicking drugs
In 2024, scientists from the Institute of Precision Medicine at Queen Mary University and the Norwegian School of Sports Sciences published in a journal Nature Metabolism a detailed review of how the human body responds to prolonged fasting. As part of the project, 12 healthy participants underwent a seven-day fast, consuming only water, and their blood was drawn daily for analysis.
Methodology and scale of measurements
Researchers measured the concentration of about three thousand different proteins in blood plasma before the start of fasting, on each of the following days, and after resuming feeding. The obtained data were compared with genetic information from large population studies, which allowed determining which biological pathways are activated or suppressed during fasting.
As expected, in the first two to three days, the body switched from using glucose from food to fat reserves. This metabolic shift has long been known, but new data showed that after the third day, deeper changes in the functioning of various organs begin to manifest.
Systemic changes after three days
Participants lost an average of 5.7 kg, with some of the mass coming from both fat and muscle tissue. However, in addition to weight loss, researchers noted changes in the levels of proteins responsible for immune response, inflammation regulation, DNA repair, and signaling between cells. Some of these changes may be potentially beneficial, such as the enhancement of autophagy processes, but others require further study due to possible risks.
The study also confirmed that the human body is evolutionarily adapted to periods of food absence – the ability to survive without food was important in conditions of unpredictable access to resources. In the modern world, fasting is practiced for religious, cultural, medical, and dietary reasons.
Historically, fasting has been used in medicine to treat epilepsy, rheumatoid arthritis, and other diseases. New results may lay the foundation for the development of 'fasting mimetics' – drugs capable of reproducing some of the biochemical effects of prolonged fasting without the need for complete food deprivation.
Scientists emphasize that it is still unclear which of the detected changes are unequivocally beneficial and which may have negative consequences. Therefore, any practices of prolonged fasting without medical supervision remain risky.
The obtained data pave the way for more targeted research that could lead to new therapeutic strategies utilizing the body's natural adaptive mechanisms.
Source: ScienceDaily
