Updated on: Wednesday, February 27, 2013
Snacking at night can make you add more kilos than munching on food during the day, according to a new study.
The study found that the body turns more of the food into fat at night, while turning it into fuel during the day.
Researchers found that mice's ability to regulate their blood sugar varied throughout the day.
In addition, disrupting their circadian clock, which signals sleep and wakefulness among other things to the body, caused them to put on more fat, LiveScience reported.
The findings could explain why night-shift workers are more prone to diabetes and obesity, researchers said.
Study co-author Carl Johnson, a chronobiologist at Vanderbilt University said, "Disrupting your biological clock leads to a disruption of metabolism such that there's more of a tendency to put on fat, even with the same amount of caloric intake or diet."
"It's not only what you eat but when you eat it that's important," Johnson said.
Several studies in the past have shown that shift workers gain more weight and are likelier to develop diabetes. Past work also showed that mice (which are nocturnal) put on more fat if they can only eat during the day, even at the same caloric intake.
Researchers suspected the circadian clock played a role, though exactly how was a mystery.
Johnson and his colleagues tested how well mice's bodies processed food across the 24-hour cycle. During daylight hours, when mice wouldn't normally eat, they were less responsive to insulin, a hormone that tells the body's tissues to take sugar from the blood so it can be used as energy.
In addition, when they disrupted the mice's circadian clocks by keeping them in dim red light all day, the mice developed signs of insulin resistance, meaning the tissues didn't respond to insulin's signal to take up sugar, and they put on more fat.
The findings hint that snacking late into the night may be worse for people than eating earlier in the day, Johnson said.
The study was published in the journal Current Biology.