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Srushti Shah/Medill

Binge eating at night - disrupting the daily biological clock - can lead to Type 2 diabetes.


Living against the clock may cause diabetes, obesity, study finds

by Srushti Shah
Feb 20, 2013


Binge eating at night can lead to obesity and Type 2 diabetes.

That admonition is suggested by a study published Thursday in the journal Current Biology by Nashville researchers suggests.

“We studied insulin sensitivity in mice,” said Carl Johnson, professor in the department of biological sciences at Vanderbilt University. “And it turns out that mice are insulin resistant during daytime, which is their inactive period.”

The researchers at Vanderbilt University studied the daily biological clock of mice and found out that mice are inactive during the daytime and active during the night, which is exactly opposite to the human cycle.

“The significance of this study is also to point out that many of these metabolic studies of insulin responses in mice have been done at the wrong time," considering that mice are inactive during the day, Johnson said.

According to the study, the metabolism rates in mice change during their active and passive periods. Also, when there is insulin resistance, the risk of Type 2 diabetes is higher. Insulin is an enzyme that plays a vital role in regulating the carbohydrate and fat metabolism levels in the body. Insulin resistance, or “lower insulin rates” in the body can lead to Type 2 diabetes, where high blood sugar levels can cause a range of symptoms including frequent urination, weakness, rapid heart beat and loss of appetite.

“In terms of humans, having a biological clock that is active and operating well is important in the way in which our food is metabolized, in terms of gaining weight or developing insulin resistance,” Johnson said.

A number of biological studies show the relationship between eating habits, obesity and diabetes. Other studies conducted by the University of California and the University of Pennsylvania study, have shown that mice gain weight at different rates when given the same amount of calories during different times of day. But the Vanderbilt study about insulin sensitivity in mice provides a more concrete floor to understand the daily biological clock.

The researchers disrupted the biological clock of the mice, by underexposing or overexposing them to light, thus breaking their rhythms. And they discovered that in both cases mice gained more fat and developed insulin resistance –both of which are pre-diabetic symptoms.

“It is indeed a very good study,” said Dr. Hossein Ardehali, an associate professor of medicine, pharmacology and biological chemistry at the Feinberg School of Medicine at Northwestern University. “There have been reports in the past that show that people who have been working nights, have higher risks of diabetes.”

This study, according to Ardehali, clearly has some clinical implications. Our hormones are produced according to our internal work shifts and are secreted during the day and disruption in circadian or daily rhythm can really affect the body, he said.

“With this study, people can become more aware,” Johnson said. “With what they eat, when they eat is also important. So having the main meal at midday is a much healthier option.”

Researchers also said that they believe that this study could help those workers who work different shifts to be more aware and careful about their eating habits. But Johnson said researchers still want to be sure about how well this study translates to humans, which would be researched next.