Prolonged fasting prompts a whole-body response which could bring health benefits aside from weight loss, the team behind a new study has said.
Researchers say that after three days of fasting, distinct changes in protein levels are seen. Understanding which proteins are involved in how the body reacts to fasting could be used to predict possible health outcomes of fasting for at least three days.
The team from Queen Mary University of London’s Precision Healthcare University Research Institute (PHURI) and the Norwegian School of Sports Sciences say it is the first time they have seen what happens at a molecular level across the body during prolonged fasting.
Prior to the study, little has been known about exactly how the body reacts to prolonged fasting and how it may impact health outcomes.
Claudia Langenberg, Director of PHURI, said: “Fasting, when done safely, is an effective weight loss intervention. Popular diets that incorporate fasting – such as intermittent fasting – claim to have health benefits beyond weight loss.
“Our results provide evidence for the health benefits of fasting beyond weight loss, but these were only visible after three days of total caloric restriction – later than we previously thought.”
Researchers monitored 12 healthy adults who followed a water-only fast for seven days. They noted any changes in the levels of 3,000 proteins in their blood before, during and after the fast. By applying genetic information from large-scale studies, the researchers could use the protein data to calculate potential health outcomes.
The researchers found that the participants lost an average of 5.7kg of both fat mass and lean mass. The fat mass stayed off after three days of eating following the fast, while the lean mass was regained almost completely.
In terms of the changes to protein levels, researchers say they indicate a whole-body response to consuming no calories whatsoever. The researchers noted that one in three of the proteins altered significantly. This included, for example, changes in proteins that provide the structure for neurons in the brain.
Further research on the back of these findings could lead to therapeutic interventions, the team say, including for those who would benefit from fasting but are unable to do so.
Maik Pietzner, Health Data Chair of PHURI, said: “Our findings have provided a basis for some age-old knowledge as to why fasting is used for certain conditions.
“While fasting may be beneficial for treating some conditions, often times, fasting won’t be an option to patients suffering from ill health. We hope that these findings can provide information about why fasting is beneficial in certain cases, which can then be used to develop treatments that patients are able to do.”
Read the study in Nature Metabolism.
