How fasting can improve your overall health

Fasting may not be just a religious or political practice. It may actually protect you against age-related diseases and improve your overall health, researchers say.

The study, led by a team from the University of California-Irvine (UCI), found that fasting affects circadian clocks in the liver and skeletal muscle, causing them to rewire their metabolism, which can ultimately lead to improved health and protection against age-related diseases.

The circadian clock operates within the body and its organs as intrinsic time-keeping machinery to preserve homeostasis in response to the changing environment. 

And, while food is known to influence clocks in peripheral tissues, it was unclear until now how the lack of food influences clock function and ultimately affects the body.

"We discovered fasting influences the circadian clock and fasting-driven cellular responses, which together work to achieve fasting-specific temporal gene regulation," said lead author Paolo Sassone-Corsi, Professor of Biological Chemistry at UCI. 

"Skeletal muscle, for example, appears to be twice as responsive to fasting as the liver," Sassone-Corsi added.

The research, detailed in the Cell Reports journal, was conducted using mice, which were subjected to 24-hour periods of fasting. 

While fasting, the mice exhibited a reduction in oxygen consumption (VO2), respiratory exchange ratio (RER), and energy expenditure, all of which were completely abolished by refeeding, which parallels results observed in humans.

"The reorganisation of gene regulation by fasting could prime the genome to a more permissive state to anticipate upcoming food intake and thereby drive a new rhythmic cycle of gene expression. 

In other words, fasting is able to essentially reprogram a variety of cellular responses," Sassone-Corsi said. 

"Therefore, optimal fasting in a timed manner would be strategic to positively affect cellular functions and ultimately benefiting health and protecting against age-associated diseases."

This study opens new avenues of investigation that could ultimately lead to the development of nutritional strategies to improve health in humans.