"The effect can be quite fast, in a matter of days," said Dr. Joe Bass of Northwestern University and Evanston Northwestern Healthcare in Illinois, whose study appears in the journal Cell Metabolism .
The researcher said the study suggests that overeating alters a central mechanism of the biological clock, modifying the internal signals that control appetite. "What we see is that the ticking clock slowed," the author in a telephone interview.
Known as circadian rhythm, the internal clock runs daily rhythms and regulates body when to sleep, wake up and eat, among many other body functions.
Risk of obesity and diabetes
Previous studies led by Bass found that a faulty clock could raise the risk of obesity and diabetes. The latest research showed that overeating can encourage this process. However, the effect would not be automatic. Humans have demonstrated in many studies to have more complex reactions that mice to changes in diet.
"If you give a mouse a diet of high fat, eat excessive amounts," said Bass. "It's like a person who eats at McDonald's or eat too much food at Thanksgiving dinner," he said.
Dietary changes include the genetic mechanism of the internal clock.
"What we found was that the expression of genes that encode the clock is altered by high-fat diets. Diet is as if the clock wore out or rust," said the author. "It erodes the abundance of proteins in cells," he added.
The study suggests that the circadian rhythm and metabolism would be closely related, so disturbing the biological clock could have a negative effect.
The research was funded by the National Institutes of Health grants U.S. and Amylin Pharmaceuticals and Eli Lilly and Co.
