Lack of sleep is thought to cause weight gain. This new research shows how.
Published in the Journal of Lipid Research, it showed that participants who slept no more than five hours each night for four consecutive nights reported feeling less satisfied after eating a high-fat, calorie-dense meal.
Blood samples showed that sleep restriction led to higher insulin levels and faster clearance of lipids from the blood. Both factors affect how fat is metabolized.
Even when the participants were allowed to recover with 10 hours of sleep for two consecutive nights, their fat metabolism was no longer the same. Their weight did, however, return to baseline levels.
Overall, the findings suggest that complex metabolic shifts occur after periods of restricted sleep. They also shed light on how sleep deprivation is associated with weight gain. In the long run, lack of sleep may raise the risk of obesity and diabetes, said lead author Kelly Ness from the University of Washington.
Lack of sleep affects insulin sensitivity and satiety
The price of insufficient sleep may be poor health. From short-term problems like excessive sleepiness to long-term ones like high blood pressure and heart ailments, previous studies suggest that lack of sleep can lead to a host of health problems.
For their study, Ness and her colleagues recruited 15 healthy male participants in their 20s to assess the effect of sleep deprivation on their postprandial lipemia, or the rise in triglyceride-rich lipoproteins after eating. These fatty substances have been linked to the formation of plaque that can clog or damage arteries.
During the trial, the men spent 10 nights in a suite in the Clinical Research Center (CRC) at the Pennsylvania State University (Penn State) after a week of getting 10 hours of sleep each night at home.
The researchers then gave them a high-fat, calorie-dense dinner of chili and pasta each night. The participants were told to get no more than five hours of sleep for four consecutive nights.
For the last two nights of the trial, participants were told to sleep for 10 hours to simulate a weekend of catch-up sleep.
Blood samples showed that sleep deprivation led to high levels of insulin, the hormone that signals cells to take up glucose from the blood. Having higher-than-normal levels of insulin affects how fat is broken down.
More lipids were also being stored as an excess source of fuel. While this extra fuel could have been beneficial in ancient times when people were more active, it is not good in a modern context where people are relatively inactive and calorie-dense foods are accessible, said senior author Orfeu Buxton from Penn State.
Most of the participants also reported feeling less full after eating their high-fat dinners while sleep-deprived. Increased fat stores, greater hunger and higher insulin levels led to weight gain.
Moreover, the two nights of catch-up sleep failed to restore the participants’ metabolic processing of fat from food, suggesting that sleep restriction causes complex metabolic shifts to occur. (Related: How sleep deprivation affects your physical and mental health.)
The National Sleep Foundation recommends that the average adult gets at least seven to nine hours of sleep every night. However, recent studies show that chronic sleep deprivation is prevalent in the United States.
Therefore, Ness and her colleagues’ findings are a wake-up call for Americans. By exposing the adverse health effects of sleep deprivation, studies like these shine the spotlight on the importance of getting adequate sleep each night for a person’s overall health and well-being.
Learn more about sleep and how it affects your health at Mind.news.