Billions of people worldwide fast regularly for religious reasons or to lose weight, but until now the full biological consequences of long-term calorie restriction were poorly understood.
By analyzing the systemic changes that occur during long periods of abstinence from food consumption in several different body organs, a group of researchers has determined the positive and negative effects of fasting on health. have revealed.
The study authors recruited 12 healthy volunteers to participate in a seven-day fasting period during which they were allowed to drink water but not eat any food. The participants were closely monitored throughout the course, and the researchers measured changes in about 3,000 different blood proteins on a daily basis.
Within the first few days of fasting, the volunteers’ bodies changed their energy sources and switched to burning stored fat instead of burning glucose. As a result, the participants lost an average of 5.7 kg during the week and maintained this weight loss even after starting the diet.
Although the researchers did not see a major change in blood protein levels during the first few days of fasting, this changed after the third day, and hundreds of compounds with important health effects fluctuated greatly.
Using past genetic studies that have linked different proteins to different diseases, the authors were able to estimate health consequences for 212 plasma compounds that changed during fasting. For example, they found that not eating for more than three days led to a decrease in plasma levels of the SWAP70 protein. Since low levels of this marker are associated with a reduced risk of developing rheumatoid arthritis, the researchers speculate that this finding may provide at least a partial explanation for pain relief in patients with the disease during prolonged fasting.
Also, there was a protein called HYOU1 in the list, which is related to coronary artery disease. During the fasting period, the levels of this compound also decreased, suggesting that continuous periods of starvation may have a beneficial effect on heart health.
The researchers also identified several negative consequences associated with fasting. For example, they observed an increase in coagulation factor XI, which is probably associated with an increased risk of thrombosis. “For the first time we can see what happens at the molecular level throughout our bodies during starvation,” study author Claudia Langenberg said in a statement. “Our results provide evidence for health benefits of fasting beyond weight loss, but these benefits were seen after three days of calorie restriction, later than we expected.”
Mike Pitzner, one of the authors of the study, summarizing the results of this research, adds that while fasting may be useful in the treatment of some conditions, this approach is often not a suitable option for people suffering from the disease.
Study findings in the journal Nature Metabolism It has been published.
