It is a well-researched fact people who sleep less have a tendency to weigh more but there is more to the theory than what previous studies were able to determine. Researchers at Penn State believe their work sheds new light on the subject as they looked at how sleep deprivation affects fat metabolism.
Professor Orfeu Buxton has been instrumental in other studies that concluded long-term sleep loss puts people at a higher risk of obesity and diabetes. But a lot of that work has been with an eye toward how sleep affects glucose metabolism. This study put the focus squarely on the digestion of lipids from food.
In a report in the Journal of Lipid Research, Buxton and his colleagues explained how lack of sleep can lead people to feel less full after eating and how it causes the body to store more fat.
Scientists had 15 healthy men in their 20s spend a week getting plenty of sleep at home before embarking on a 10-night trial in a sleep lab. Five of the nights the subjects spent no more than five hours in bed. Researchers fed the participants a standardized high-fat dinner which consisted of a bowl of chili mac.
"It was very palatable—none of our subjects had trouble finishing it—but very calorically dense," researcher Kelly Ness said. But she went on explain that meal left most of the participants feeling less satisfied than it did after they ate it while well-rested.
Scientists compared blood samples from the study participants and found sleep deprivation affected the lipid response after the meal which led to fat clearing from the blood faster after eating. Buxton explained this could predispose people to putting on weight because, “The lipids weren’t evaporating – they were being stored,” he said.
After a simulated work week of deprivation, participants were able to spend 10 hours in bed to catch up on missed sleep as someone would typically do on a Saturday or Sunday. They were given the same meal of chili mac after the first night of good rest. Researchers observed the participants had slightly better fat metabolism but it did not return to the healthy baseline level recorded before the trial.
While Buxton said the trial was not necessarily a perfect model for the real world because it was so highly controlled and only involved healthy young men, he did say it gives worthwhile insight into how we handle fat digestion.
"This study's importance relies on its translational relevance,” he said. “A high-fat meal in the evening, at dinnertime—and real food, not something infused into the vein? That's a typical exposure. That's very American."