Staying up late every night and sleeping in is a habit that could put you at risk for gaining weight. People who go to bed late and sleep late eat more calories in the evening, more fast food, fewer fruits and vegetables and weigh more than people who go to sleep earlier and wake up earlier, according to a new Northwestern Medicine study.
Late sleepers consumed 248 more calories a day, twice as much fast food and half as many fruits and vegetables as those with earlier sleep times, according to the study. They also drank more full-calorie sodas. The late sleepers consumed the extra calories during dinner and later in the evening when everyone else was asleep. They also had a higher body mass index, a measure of body weight, than normal sleepers.
The study is one of the first in the United States to explore the relationship between the circadian timing of sleeping and waking, dietary behavior and body mass index. The study was published online in the journal Obesity and is expected to appear in a late summer print issue.
"The extra daily calories can mean a significant amount of weight gain – two pounds per month – if they are not balanced by more physical activity," said co-lead author Kelly Glazer Baron, a health psychologist and a neurology instructor at Northwestern University Feinberg School of Medicine.
"We don't know if late sleepers consume the extra calories because they prefer more high-calorie foods or because there are less healthful options at night," said co-lead author Kathryn Reid, research assistant professor in neurology at the Feinberg School.
The study shows not only are the number of calories you eat important, but also when you eat them -- and that's linked to when you sleep and when you wake up, noted senior author Phyllis Zee, M.D., professor of neurology and director of the Sleep and Circadian Rhythms Research Program at Feinberg and medical director of the Sleep Disorders Center at Feinberg and Northwestern Memorial Hospital.
"Human circadian rhythms in sleep and metabolism are synchronized to the daily rotation of the earth, so that when the sun goes down you are supposed to be sleeping, not eating," Zee said. "When sleep and eating are not aligned with the body's internal clock, it can lead to changes in appetite and metabolism, which could lead to weight gain."
The research findings could be relevant to people who are not very successful in losing weight, Zee said. "The study suggests regulating the timing of eating and sleep could improve the effectiveness of weight management programs," she said.
The findings also have relevance for night-shift workers, who eat at the wrong time of day related to their bodies' circadian rhythms. "It's midnight, but they're eating lunch," Zee said. "Their risk for obesity as well as cardiovascular, cerebrovascular and gastrointestinal disorders is higher."
The study included 51 people (23 late sleepers and 28 normal sleepers) who were an average age of 30. Late sleepers went to sleep at an average time of 3:45 a.m., awoke by 10:45 a.m., ate breakfast at noon, lunch at 2:30 p.m., dinner at 8:15 p.m. and a final meal at 10 p.m. Normal sleepers on average were up by 8 a.m., ate breakfast by 9 a.m., lunch at 1 p.m., dinner at 7 p.m., a last snack at 8:30 p.m. and were asleep by 12:30 a.m.
Participants in the study recorded their eating and sleep in logs and wore a wrist actigraph, which monitors sleep and activity cycles, for at least seven days.
Late sleepers function in society by finding jobs where they can make their own hours, Baron noted, such as academics or consultants. "They find niches where they can live this lifestyle, or they just get by with less sleep," she said.
Northwestern researchers are planning a series of studies to test the findings in a larger community and to understand the biological mechanisms that link the relationship between circadian rhythms, sleep timing and metabolism.
The research was supported by the National Heart, Lung and Blood Institute of the National Institutes of Health.
Marla Paul | EurekAlert!
Researchers release the brakes on the immune system
18.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
18.10.2017 | Materials Sciences
18.10.2017 | Physics and Astronomy
18.10.2017 | Physics and Astronomy