Khaberni - A scientific study revealed that abstaining from food for several days does not only limit its effect to fat burning, but also induces widespread biological changes that include the brain, the immune system, and the metabolic process.
This study was published in the prestigious journal Nature Metabolism, and found that most of these important effects do not appear immediately, but the body needs about three days of fasting to enter a completely different biological state.
These findings provide the clearest picture to date of what happens inside the human body at the molecular level during prolonged fasting, and researchers hope that this will help in the future development of treatments that mimic the benefits of fasting without the need to abstain from food for consecutive days.
To understand what happens to the body during extended fasting, researchers from Queen Mary College in London and the Norwegian School of Sport Sciences followed 12 healthy volunteers who fasted for 7 consecutive days consuming only water, collecting daily blood samples before, during, and after fasting.
Using advanced techniques to analyze proteins, the team was able to track about 3,000 proteins in the bloodstream, where these proteins serve as indicators of what is happening inside the various organs and tissues.
As expected, the body switched from burning glucose to burning fats during the first two or three days of fasting, and participants lost an average of about 5.7 kilograms of fat and muscle tissue together.
After returning to eating for 3 days, their bodies regained most of the lost muscle tissue while most of the lost fat remained.
However, the surprise was that the major molecular changes did not start immediately but became more noticeable after about 3 days of consuming no calories. More than a third of the proteins measured changed significantly during fasting, and the strongest changes were associated with proteins that help provide structural support to tissues and organs, including nerve cells in the brain.
Importantly, these changes were remarkably consistent among all volunteers, indicating that the body follows a highly coordinated response to prolonged fasting.
Claudia Langenberg, director of the Institute for Precision Healthcare Research at Queen Mary, commented that this is the first time it has been possible to see what happens at the molecular level throughout the body during fasting, adding that safe fasting is an effective way to lose weight, but their study results proved that the health benefits that go beyond weight loss do not appear until three days after complete calorie deprivation, which is later than previously thought.
The researchers also used genetic data from large human studies to examine the impact of fasting-associated protein changes on long-term health, finding potential links to improvements in biological pathways associated with the risk of disease and inflammation, as well as changes in proteins involved in supporting brain structure.
Recent years have seen an increased interest in fasting research, linking intermittent fasting to improvements in insulin sensitivity, lipid levels, brain function, and cardiovascular health. Other studies have found that the body enters a deep ketogenic state during fasting for several days, significantly altering how cells use fuel.
However, on the other hand, researchers warned that extended fasting is not without risks. A subsequent study in protein science on long water fasting found evidence of a temporary increase in inflammation, platelet activation, and changes in blood clotting pathways, which are effects that may represent temporary stress responses and require further research to understand their long-term consequences.
Extended fasting also increases the risk of dehydration, mineral imbalance, dizziness, and muscle loss, especially for people with chronic diseases such as diabetes, eating disorders, and heart disease. For this reason, extended fasting should not be attempted without medical supervision.
What excites scientists more than anything else is the timing of the body's response; many popular fasting methods focus on short fasting periods, but this study suggests that the most dramatic molecular changes may require several days of complete calorie deprivation.
Mike Bitzner, one of the participating researchers, said their findings provided a basis for some ancient knowledge about why fasting is used for certain conditions, adding that since fasting is often not an option for patients with health conditions, they hope these findings will help develop treatments that mimic the fasting benefits and can be used by patients.
