Article image

Fasting triggers remarkable changes throughout the body

For centuries, fasting has held a prominent place in various cultures and religions, lauded for its cleansing and revitalizing properties. Could the age-old tradition of fasting hold the key to unlocking transformative changes within the human body?

To answer this intriguing question, researchers at Queen Mary University of London’s Precision Healthcare University Research Institute (PHURI) embarked on a unique experiment. 

Twelve volunteers bravely agreed to participate in a 7-day water fast. While closely monitoring their health, the researchers aimed to paint a comprehensive picture of how our bodies react when deprived of food. 

Three-day turning point in body changes

The study revealed a key turning point in how the body responds to several days of fasting. In the first few days, the body switches from using sugar for energy to burning fat stores, which is known as ketosis. This is the body’s initial response to ensure it has enough energy to survive.

However, after three days of fasting, the body initiates a broader response that involves changes in its various organs and systems. These changes include adjustments in proteins that support the brain, the immune system, and potentially even cellular repair. This suggests that the body enters a different state, focused on efficiency and protection during times of low food availability.

Fasting triggers a body-wide response

The researchers carefully studied nearly 3,000 proteins in the blood of volunteers. Surprisingly, about a third of the proteins changed significantly during the fasting period. These proteins, found in various organs and involved in diverse biological processes, indicate that fasting triggers a body-wide response instead of isolated changes in specific areas.

Interestingly, the changes in protein levels were consistent across all participants, despite differences in gender and individual health. This consistency suggests a fundamental and deeply ingrained response to fasting, a built-in mechanism in the human body. It’s a universal biological process that activates to handle the absence of incoming nutrients and optimize functioning during such conditions.

The extracellular matrix

Fasting also alters the proteins found in the brain’s network of support structures, called the extracellular matrix. This network provides structure and biochemical support for brain cells

Changes in the extracellular matrix can significantly impact brain function, affecting everything from the health of brain cells to how effectively they communicate with one another. These findings on suggest that fasting could have positive consequences for brain health. 

Study significance 

“For the first time, we’re able to see what’s happening on a molecular level across the body when we fast,” explained Claudia Langenberg, Director of PHURI. 

“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.”

Broader implications 

By understanding how fasting works at a deeper level, scientists might be able to develop treatments that mimic its benefits without needing actual fasting. This knowledge could also help address modern health issues like obesity and diabetes by providing a basis for new dietary recommendations or interventions that use fasting principles to improve health. 

“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, oftentimes, fasting won’t be an option to patients suffering from ill health,” noted study co-author Maik Pietzner, Health Data Chair of PHURI.  

“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,

The study is published in the journal Nature Metabolism.


Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and


News coming your way
The biggest news about our planet delivered to you each day