Excessive eating at night has always been associated with weight gain. And now experts are finding out why.
A recent Northwestern University study found that eating at the "wrong" time could time leads to twice as much weight gain, even if the amount of calories consumed are the same as those eaten at the right times.
This research, which is published online in the journal Obesity, is limited to animals, but the results were remarkable enough to indicate a need for further human research, claims the study’s lead author, Deanna Arble, a PhD student at Northwestern University.
According to Arble, ”We’ve found that mice who are allowed to eat during the light phase — their ‘wrong’ time of day — gain substantially more weight than those allowed to eat during the dark phase, the right time of day for them to eat."
However, Arble says that based on their research, it is not possible to set an optimal time window for people to eat to maintain weight. Rather, she hopes that their finding will prompt obesity scientists to concentrate more closely on the concept of timing eating.
In the study, the researchers fed two groups of nocturnal [expected to eat at night] mice the same high-fat diet. They fed one group in the morning and the other at night. Both groups were allowed to eat as much as they want during the 12-hour feeding phase.
Wrong time vs. Right time
At the end of the 6-week study period, the mice that were fed during the "wrong" time [morning], gained more weight than those who were fed during the "right" time [night].
When the researchers compared the mice’s weight at the start of the study to their weight at the end, they found that those who at the wrong time had a 48 percent weight increase, while those who ate at the right time only had a 20 percent weight increase. Though both groups gained weight, the animals that ate at the wrong time put on twice as much weight. "We did not restrict the amount of calories they were eating," says Arble. Yet still, between the 2 groups ”there was no difference in the [average] amount of calories consumed." The only variable was when the food was consumed.
Arble says they can not say for certain why the mice who ate at the wrong time gained more weight. We speculate that it’s the interplay between body temperature, metabolic hormones such as leptin, and the sleep-wake cycle," she says.
Arble explains that for humans, nighttime is a time for rest as the body temperature drops. "Eating at night is contradicting your body’s natural circadian rhythm,” she says."The leptin levels are starting to rise, and are supposed to be discouraging you from eating." Rising leptin levels suppress appetite.