Nightly Snacking May Speed Weight Gain
Sept. 4 -- THURSDAY, Sept. 3 (HealthDay News) -- Late-night forays to the fridge might have you packing on the pounds even faster than munching during the day does, a new mouse study suggests.
That's because the body's internal clock, or circadian rhythm, may play a role in metabolism, researchers say.
"We have found causal evidence that eating during the 'wrong' circadian time leads to weight gain in mice," said lead researcher Deanna Arble, a doctoral candidate in Northwestern University's Center for Sleep and Circadian Biology.
"While I do not believe the field is advanced enough to prescribe appropriate eating times for each individual, I believe we can at least say that humans should avoid eating during their normal sleeping phase because this could lead to increased weight gain," she said.
The report is published in the Sept. 3 online edition of Obesity.
Over six weeks, Arble's team fed two groups of mice a high-fat diet. The animals were allowed to eat as much as they wanted. Some mice were fed during the day -- normal sleeping time for mice - while others were fed at night, when they are typically most active.
The researchers found that changing the feeding time, by itself, affected the rodents' body weight. Mice fed during their normal sleeping hours gained more weight than mice that ate during their typical wakeful hours.
In fact, mice that ate during normal sleeping hours gained 48 percent more weight over their weight at the start of the study, while the animals fed during normal wakeful hours gained only 20 percent more weight.
The mice fed during their normal sleep-time also had an almost 8 percent higher level of fat as a percentage of overall weight, the team said.
All of the mice took in the same number of calories and expended about the same amount of energy, although the mice that ate at the "wrong" time had somewhat less activity, the researchers noted.
"We have demonstrated that mice eating at the 'wrong' time of day have increased weight gain compared to mice eating at the 'right' time of day," Arble said.
