Have you put on a few inches around your waist lately? Maybe you’re eating more. On the other hand, maybe you’re sleeping less, suggests a new study from researchers at the Mayo Clinic College of Medicine in Rochester, Minnesota. The report was published in The Journal of the American College of Cardiology.
The researchers began with the observation that more than one-third of adults in the United States commonly fail to get enough sleep because of their choices, such as spending too much time on social media or working at night. But what interested the researchers was the possible effect of sleep deprivation on weight and fat accumulation, making their study the first to evaluate the effect of sleep loss on the distribution of body fat. According to author Virend Somers, MD, director of the Cardiovascular Facility and the Sleep Facility within Mayo Clinic’s Center for Clinical and Translational Science, “Our work focused on people who chose to sleep less. It wasn’t about insomnia, so much as, say, a student in college who decides they find it necessary to sleep less for a while in order to get their work done.”
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The authors enlisted the aid of 12 healthy volunteers aged 19 to 39, none of whom were rated “obese.” The first four days of the test period were considered an acclimation phase, during which the subjects were given nine hours in bed to sleep. Then they were randomly assigned to two lab study periods, each lasting 21 days. In the first phase the subjects were subject to substantial sleep reduction—just four hours per night. No sleep reduction was imposed in the second phase, which consisted of nine hours sleep. Then the participants were given three days and nights of recovery with nine hours in bed for both groups.
During both phases, Dr. Somers explained, “We monitored all the food they had, but they could eat or order anything they wanted.” The researchers observed the volunteers’ appetite, energy intake and expenditure, body weight and composition, and fat distribution, especially visceral fat. As opposed to subcutaneous fat, which is stored beneath the skin, visceral fat, sometimes called “hidden fat,” is stored deep in the body and is wrapped around internal organs such as the stomach, liver, and intestines.
After the study period, it was found that the subjects consumed more than 300 extra calories per day during the sleep restriction phase, which amounted to approximately 13% more protein and 17% more fat than in the acclimation stage. The rise in consumption was at its highest in the early days of the sleep deprivation phase, after which it dropped off during the recovery phase to the initial levels. Energy expenditure, however, remained about the same throughout.
More food and equal energy expenditure — an obvious formula for weight gain. But to the researchers’ surprise, the volunteers did not put on a lot of pounds. What they did experience, however, was an increase in visceral fat of 11%, a rise Dr. Somers called “stunning.” He explained that although you can’t see visceral fat, it’s “actually the most dangerous fat.” Visceral fat, he said, “produces all kind of toxic things that cause heart and blood vessel disease,” including high blood pressure, high blood sugar, and high cholesterol — all of which can notably elevate the risk for developing diabetes.”
Dr. Somers went on to say, “We don’t know why this happened. We also don’t know what this might mean for people who are already obese or for people who struggle with insomnia that they can’t control. That will be for future research. But what we can tell already is that even for healthy people who lose sleep by choice, this is not a switch you can readily turn off once you turn it on. And what’s really important to understand here is that catch-up sleep — after sleep loss — will not necessarily bring you back to normal. If you are going to be sleep-deprived for a prolonged period you should pay particular attention to how much food you eat and what your food choices are. And be more conscientious about exercising.”
Want to learn more about sleeping well with diabetes? Read “Getting the Sleep You Need,” “Eating for Better Sleep” and “Feeling Fatigued: Here’s How to Fight It.”