Posted on Sep 12, 2018, 6 p.m.
Mice lacking biological clocks were found to be protected against obesity and metabolic disease by having access to food restricted to a ten hour window, as published in the journal Cell Metabolism.
Scientists from the Salk Institute suggest health problems associated with disruptions to 24 hours rhythms of activity and rest can be corrected by consuming all calories within a 10 hour window. Many people start the day off to do whatever they had planned with the day ending with a bedtime snack around 14-15 hours later; restricting caloric intake to within 10 hours a day and fasting the rest is suggested to lead to better health regardless of biological clocks.
All cells in mammal bodies operate on 24 hours cycles called the circadian rhythm, for humans digestive genes are more active earlier in the day while cellular repair genes are more active at night time as an example. In previous studies mice allowed 24 hour access to high fat food became obese and developed metabolic diseases. When these same mice on the same diet were restricted to eating daily within an 8-10 hour window they became lean, fit, and healthy which was attributed to keeping the animals in better sync with their cellular clocks.
In this study to gain better understanding of the role of circadian rhythms in metabolic disease genes responsible for maintaining biological clocks were disabled including in the liver which regulates many metabolic functions; the genetic defects in clock-less model mice make them prone to obesity, diabetes, fatty liver disease, and elevated blood cholesterol which is further escalated with fatty and sugary diets. To test whether time restricting calorie intake would benefit these animals they were put onto one of two high fat diet regimes: one group with access to food around the clock; and another group with access to the same caloric count only in a ten hour window. The unlimited access group became obese and developed metabolic diseases; the ten hour window group remained lean and healthy despite not having an internal biological clock.
New work suggest primary role of circadian clocks may be to tell when it is time to eat and when not to, internal timing strikes balance between sufficient nutrition during fed state and necessary repair or rejuvenation during fasting. When disrupted such as in shift work or compromised due to genetic defects balance between nutrition and rejuvenation breaks down and diseases set in, according to the researchers.
With age circadian clocks weaken, age dependent deterioration parallels increased risks for metabolic disease, cancer, dementia, and heart diseases. Simple lifestyle changes such as limiting all caloric intake to a ten hour window is suggested to restore balance and stave off metabolic disease and help maintain health, according to the researchers; finding a good lifestyle can help beat bad effects of defective genes that may open new hope to stay healthy.
Plans are underway to investigate whether eating within a 8-10 hour window can help prevent or reverse age related disease, as well as looking at how to apply results to humans. Worldwide anyone can log into their website to sign up for studies, or download apps and receive help on how best to adopt optimum daily eating fasting cycles. It is hoped by collecting data of daily eating and health status from thousands of people it may lead to gaining better understandings of how daily eating fasting cycle sustain health. Their website can be found at: http://mycircadianclock.org/
Materials provided by Salk Institute.
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Amandine Chaix, Terry Lin, Hiep D. Le, Max W. Chang, Satchidananda Panda. Time-Restricted Feeding Prevents Obesity and Metabolic Syndrome in Mice Lacking a Circadian Clock. Cell Metabolism, 2018; DOI: 10.1016/j.cmet.2018.08.004