It's no secret that eating fatty foods can add inches to your waistline. But a new study suggests that a high-fat diet can also disrupt the body's biological clock - and possibly lead to nighttime binge eating, making a bad situation even worse.
The body's internal clock, known as the circadian rhythm, helps to regulate when we wake up, go to sleep and many other basic functions such as the urge to eat.
In a study of laboratory mice, U.S. researchers discovered that overeating seems to throw off the timing of these internal signals, including appetite control. The rodents started eating when they should have been at rest or asleep.
"For a human, that would be like raiding the refrigerator in the middle of the night and binging on junk food," said Joe Bass, the study's lead researcher at Northwestern University in Evanston, Ill.
As part of the study, the researchers first fed mice a normal diet for two weeks. Then the mice were divided into two groups, with one continuing on regular food while the other group was switched to a high-fat diet. (About 45 per cent of the calories came from fat.)
Within a few days of altering the diet, there was an abrupt change in behaviour among animals consuming the fatty food. Their normal sleep-wake cycle was lengthened by a significant amount and they started eating during the day, when nocturnal mice are supposed to be at rest.
There was no change in the rodents on the regular diet. All the mice were kept in total darkness, so their behaviour reflected only the workings of their internal clocks.
The high-fat diet seems to set in motion a "vicious cycle," Dr. Bass said. Once weight gain starts, the body's clock is upset, which exacerbates the original problem.
"They are not only losing their capacity to control the amount that they eat, they are also doing it at the incorrect time in their sleep-wake cycle," he said. And the timing of eating could possibly influence how many of those extra calories lead to weight gain.
"When you eat, what ensues is the release of hormones that orchestrates the digestion, storage and utilization of that energy you consumed," Dr. Bass explained. This complex process is probably supposed to occur during a certain window of time during the sleep-wake
cycle so the body "functions optimally."
Mice, of course, are not humans. But Dr. Bass, whose study was published in the journal Cell Metabolism, believes a similar shift in the body's clock may be happening in people who gorge on fatty foods.
Dr. Bass said many factors contribute to being overweight. A shift in the body's internal clock could be "an additional component in that process."
Cancer and the Pill
Doctors have long known that women who take birth control pills have a slightly elevated chance of developing cervical cancer. But they weren't sure how long that danger lasted. For instance, does it go away once a woman ceases the use of the oral contraceptives?
Now a new study, based on a detailed assessment of 24 previous trials from around the world, indicates that the elevated risk begins to fall as soon as a woman stops taking the Pill. And, after a decade, the woman's odds of getting cervical cancer are the same as those for women who have never taken the hormone-based contraceptives.
"I think this is relatively reassuring," said lead researcher Jane Green at the University of Oxford.
Cervical cancer is caused by the human papillomavirus, commonly known as HPV. Many women are infected with the sexually transmitted virus but never go on to develop
the cancer. And researchers don't yet know why oral contraceptives seem to boost the chances of actually getting the cancer - although they have a few theories.
